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Fossils In Millard County, Utah

Explore two world-famous Paleozoic Era fossil localities

Find fossils 505 and 475 million years old

Click on image for a larger view. A panoramic view across the world-famous Wheeler Amphitheater trilobite beds, Millard County, Utah. Here, a commercial fossil quarrying operation allows visitors to collect, for a reasonable fee, trilobites and other paleontologic specimens (including brachiopods, sponges, and echinoderms) in the middle Cambrian Wheeler Shale, approximately 505 million years old. Innumerable perfect, complete trilobites from this locality representing, primarily, a species called Elrathia kingii have found their way into museums and private collections all across the globe. All lighter-colored strata in middle-ground to just below the prominent cliff face on peak in upper center of photograph belong to the trilobite-rich Wheeler Shale; distinctive massive cliff face at top of peak is the middle Cambrian Marjum Formation. A Google Earth image I processed through photoshop.

Field Trips To Wheeler Amphitheater And Fossil Mountain

Part 1--Wheeler Amphitheater

Millard County in western Utah is world-famous for its early Paleozoic fossil localities--a vast, sparsely inhabited area that holds numerous prolific paleontologic places of middle Cambrian through early Ordovician geologic age some 510 to 470 million years old. Indeed, this eastern Great Basin Desert region could well hold the best preserved and most complete succession of 510 to 485 million year-old middle to late Cambrian trilobites in the world. The renowned Wheeler Amphitheater locality in particular--also called Antelope Spring--in the House Range attracts eager paleontology enthusiasts year-round to an extraordinarily productive commercial fossil quarrying operation, where for a reasonable fee visitors may collect common, complete trilobites from the middle Cambrian Wheeler Shale, around 505 million years old; these include prodigious numbers of stunning specimens of a genus-species scientists call Elrathia kingii, probably the single most readily recognizable trilobite variety on earth. It is indeed a world-class fossil district.

While Cambrian trilobites continue to draw fossil seekers to these breathtakingly beautiful Great Basin environs, there are numerous additional sensational paleontologic localities scattered across Millard County.

Probably the best of the lot is Fossil Mountain in the informally designated Ibex District. Here can be found a veritable treasure trove of wonderfully preserved invertebrate fossils dating from the early Ordovician age of approximately 485 to 470 million years ago. Among the fossil groups documented from Ibex are algae, brachiopods, bryozoans, corals, cephalopods, conodonts, echinoderms, gastropods, graptolites, ostracods, pelecypods, sponges, and trilobites. Preservation of the brachiopods in particular rivals that of the Midwest region of the United States--specimens universally regarded as the most exquisitely preserved late Paleozoic (Mississippian, Pennsylvanian, and Permian Periods) organisms in the world. Around 3,500 feet of lower Ordovician sedimentary rocks are exposed at Ibex, and the material is for the most part unmetamorphosed by the geologic forces of heat, pressure, and hydrothermal alteration--pervasive processes that have invariably obliterated much ancient animal life in Paleozoic Era strata exposed throughout the western United States.

An excellent place to begin a Millard County paleontology adventure is of course Wheeler Amphitheater in the House Range, or as many fossil aficionados prefer to call the rich region: Antelope Spring. That's where the fabulous middle Cambrian Wheeler Shale attains its ultimate geological and paleontological development, where quite conveniently that successful commercial fossil dig allows visitors to come on in and collect for a reasonable fee any number of whole, perfect trilobite carapaces.

The history of fossil collecting at Wheeler Amphitheater probably begins with the prehistoric Ute Indians, who archaeologists aver used not a few of the extinct arthropod trilobites as amulets to help repel injury during battle. But there is no doubt that a Henry Engelmann, who accompanied geologist J. H. Simpson on the very first earth science expedition to Millard County in the mid 19th Century, made the initial historic recorded trilobite find at Antelope Spring in 1859. Simpson eventually provided paleontologist/geologist Fielding Bradford Meek with the Wheeler Amphitheater trilobites Engelmann had collected during the Utah explorations--specimens that Meek described for the first time in a peer-reviewed scientific paper in 1876, shortly before his death. In the early 1870s geologist G. K. Gilbert, aware of Engelmann's fossil discoveries, visited Antelope Spring and measured upwards of 2,300 feet of middle Cambrian strata, collecting in the process numerous trilobites subsequently identified and described by famous Cambrian paleontologicst C. D. Walcott, who during expeditions to Wheeler Amphitheater in 1903 and 1905 not only recovered additional abundant fossil material, but also measured the entire middle to late Cambrian sequence exposed in the general vicinity--a sedimentary succession now known to contain the following geologic rock formations: middle Cambrian Howell Limestone; middle Cambrian Dome Limestone; middle Cambrian Swasey Limestone; middle Cambrian Wheeler Shale; middle Cambrian Marjum Formation; middle Cambrian Weeks Limestone; upper Cambrian Orr Formation; and upper Cambrian Notch Peak Formation (uppermost part is lower Ordovician). Walcott officially named what's now universally recognized as the world-famous middle Cambrian Wheeler Shale in a scientific paper in 1908. After Walcott's contributions, the proverbial paleontological flood gates open on scientific exploration of the House Range and its incomparable middle to late Cambrian geologic section; scientific research papers now abound.

At Wheeler Amphitheater, only a rather narrow 17-foot thick section in the upper portions of the middle Cambrian Wheeler Shale produces significant concentrations of fossil remains. This is the precise interval that's presently mined commercially for paleontologic specimens, having operated more or less continuously since the late 1960s when an enterprising entrepreneur recognized that, fortuitously, the richest trilobite horizon occurred in an easily accessible valley or "amphitheater" on Utah state-owned lands, which could legally be leased for natural resource exploitation.

While collecting within that specific 17-foot thick zone of optimal trilobitic presence, fossil seekers catch on pretty quickly that despite the common occurrence of exceptionally well preserved trilobite exoskeletons in the rocks--most often discarded arthropod molts, shed each time the animal underwent a spurt of growth (identical to modern arthropod insects, crabs, and spiders who during growth cycles regularly drop their old body armor for newer external coverings)--only three species pop up with any kind of regularity. These include Elrathia kingii (the most famous trilobite in the world), Asaphiscus wheeleri, and Peronopsis interstricta. Much rarer trilobite finds invariably constitute carapaces of Bolasidella housensis, Alokistocare harrisi, and Olenoides nevadensis. Excluding casual surface collecting atop the numerous spoils piles, searching for prize specimens others might have left behind or overlooked (a method that often discloses excellent material, by the way), the most efficient collecting method is to attempt to spit sizable shale chunks along their original planes of sedimentary deposition with a geology rock hammer/pick. An optional technique involves utilizing a selection of well-tempered chisels in combination with the rock pick.

What you'll find in both instances is that with a gentle, firm rapping the trilobites tend to pop out of the rocks whole and complete, often in an essentially perfect state of preservation. This unusual style of fossil occurrence developed when dolomite (magnesium carbonate) precipitated in the trilobite carapaces, forming in effect "trilobite nodules" that only await a patient collector to crack them free. Practical experience has demonstrated here that on average most collectors find anywhere from 10 to 20 trilobites in a four-hour period; the majority of trilobites unearthed range from under an inch to two inches in length. Occasionally a few specimens could reasonably require special prepping with perhaps an abrasive air scribe, to remove sedimentary particles that obscure key features of the trilobites, although in actual fact most finds need little more than a careful washing with water and a toothbrush. Sometimes, though, it's aesthetically appropriate to retain trilobites in their natural state of preservation--still residing along the bedding planes of the middle Cambrian Wheeler Shale, where they dropped to a tropical sea floor accumulating silty detrital particles some 505 million years ago.

At that distant middle Cambrian date, today's Wheeler Amphitheater existed as unlithified marine muddy ooze at rather shallow depths several miles off the northwestern coastline of an ancient continent geologists call Laurentia--the paleo-precursor to what eventually became North America--then situated slightly north of the equator in what's today the southern Bay of Bengal, between India and Thailand. Over the course of geologic time, continental drift has carried the once-tropical trilobite beds northeastward thousands of miles into the temperate latitudes of present-day North America, where they now outcrop within the eastern reaches of the Great Basin Desert.

Within the House Range geographic province, paleontologists have identified some 35 species of trilobites from the middle Cambrian Wheeler Shale, although such extinct arthropods aren't the only fossil varieties waiting to be found. Also present in less frequent numbers are brachiopods; echinoderms, including an eocrinoid ("dawn crinoid") called Gogia; Phyllocarids (a bivalve crustacean with only two known living members)--including the extinct Brachiocaris and Pseudoarctolepsis; such early siliceous sponges as Diagonella, Choia, and Chancelloria; an early Chelicerate (horseshoe crabs, sea spiders, and arachnids are living members) called Esmeraldella; Naraoia, a so-called trilobitomorpha, or "soft-bodied trilobite"; Anomalocaris, the largest predator of the Cambrian seas; annelids (the worms), including famous Wiwaxia, which was first described from the astounding middle Cambrian Burgess Shale of Canada; and 20 species of non-mineralized arthropods unrelated to trilobites--in other words, soft-bodied animal remains rarely encountered in the fossil record.

In general, the soft-bodied fauna occurs in sedimentary layers where skeletonized animals remain absent; why this is so puzzled investigating paleontologists, until a recent taphonomic analysis of the Wheeler Shale fossil beds disclosed that Elrathia trilobite-dominated biofacies accumulated under dysaerobic conditions (low oxygen levels) that allowed frequent bioturbation (organisms burrowing through the unconsolidated muds)--fasciliating rapid decomposition of soft tissues in the presence of greater oxygen content--whereas the non-mineralized (soft-bodied) creatures were preserved when decay-inducing bacterial activity and bioturbation became restricted by anoxic sediments lacking oxygen.

I first visited Wheeler Amphitheater several years ago during a three-week summer vacation with my parents to eastern Nevada and western Utah. From our base camp at Baker Creek Campground in Great Basin National Park, Nevada (campsite #16, by the way--elevation roughly 7,500; Great Basin NP is a terrific place to visit when exploring the world-class paleontology of Millard County) we headed out to classic Wheeler Amphitheater in dad's old ruggedly reliable 1979 American Motors Corporation (AMC) CJ7 jeep he'd purchased in Olathe, Kansas. I recollect that we gassed up in Baker, Nevada, grabbed a few snack items and associated carbonated beverages (AKA, sodas), then moved out into the brilliant early eastern sun along a lonesome stretch of asphalt. Probably we spotted no more than three or four vehicles during the entire journey through timeless expanses of eastern Great Basin Desert. As navigator and lead research archivist for the Millard trek, I kept all pertinent road maps and scientific documents close at hand, prepared for quick inspection should contingency referencing become necessary.

What I remember distinctly is that we found the correct turnoff to Wheeler Amphitheater without difficulty. Easily spotted, indeed. After maneuvering along a system of surprisingly well-graded dirt roads through stupendous isolation, we reached our desert destination bursting with keen anticipation of a joyful paleontological adventure. We were not disappointed. For the next four hours or so we moved about the commercial quarry with a fevered zeal, splitting 505 million year-old middle Cambrian Wheeler Shale to find within several excellently preserved Elrathia kingii trilobites that popped out of their muddy matrixes whole and intact with but a gentle rock hammer tapping. This was discovery ecstasy.

505 million years earlier we would have been floating atop a warm, shallow sea off the northwest coast of North America's ancestral continental mass situated slightly north of the equator at the southern end of today's Bay of Bengal, between India and Thailand. With living trilobites below us, the sun shines roughly four percent dimmer than at Wheeler Amphitheater in a sky whose atmospheric carbon dioxide levels exceed an approximated 4,000 parts per million--at least ten times higher than CO2 readings of earth's last 100 Recent years--and average temperatures approach 77 degrees Fahrenheit, 27 degrees higher than a little over a half billion years hence. A look shoreward from the Cambrian sea discloses a landscape devoid of vegetation and animal life--an early Paleozoic scene reminiscent of portions of the Great Basin Desert, as observed from a distance in a moving vehicle through Millard County to Wheeler Amphitheater some 505 million years later.

Part 2--Fossil Mountain

After visiting classic Wheeler Amphitheater to sample an amazing concentration of trilobites in the middle Cambrian Wheeler Shale, it's time for a rendezvous with Fossil Mountain in the Ibex District--a regional Millard County locale named for a European wild goat in the 1890s by English immigrant Jack Watson, who established a post office on property he homesteaded a few miles north of what later became known as Fossil Mountain, proper.

The abundant fossil organisms at Ibex and Fossil Mountain occur in the roughly 485 to 470 million year-old lower Ordovician Pogonip Group, an association of six distinct and easily identifiable geologic rock formations. This major stratigraphic succession can be traced throughout western Utah and extreme eastern Nevada (the Pogonip Group of eastern California is composed of several different formations), but nowhere is it as fossiliferous as in the Ibex area, where silty carbonate beds several feet thick often consist of nothing but exceptionally well preserved brachiopods, gastropods, ostracods, trilobites, or echinoderms--each animal type characteristically contributing its specific remains solely to an individual shell bed, to the exclusion of all other invertebrate varieties. Such technically termed monotypic shell beds are extensively developed in the Pogonip at Ibex's Fossil Mountain, and the fossil-saturated ledges can be followed for considerable distances.

I had long heard reports of the remarkable paleontologically prolific formations of the Ibex District--had even viewed stunning brachiopod specimens from the lower Ordovician Kanosh Shale exposed there. Nevertheless, I was dutifully skeptical of the reportedly extensive, bountiful fossil occurrences. Many times in the past I'd been given "reliable" information about a rave-review region, only to find out that it could not live up to its advance billing. A fossil dealer at a mineral show once touted Ibex, talking on and on about the unbelievable abundance of fossils available there, but at the time I was busy researching another specific locality and his credible recommendations went over my head.

At a rock shop in Calico Ghost Town, in California's Mojave Desert a few miles east of Barstow, the proprietor made a special point of showing off his Millard County specimens, including chunks of brachiopod material from Ibex that were beyond belief. By now my interest in the region was solidifying, but there just didn't seem to be any spare time to get away and properly explore the place.

When at last I finally made the trip to Ibex, I was not disappointed. As the well-worn saying goes, you have to see it believe it. The rocks are relatively flat-lying, in a horizontal bedding orientation, and erosion has created natural ledges along these bedding planes. Fossil hunters can simply hike along the strike of the strata--in other words, along the horizontal direction of the rock layers--and pick of free-weathered fossils at will, in addition to innumerable quality chunks of fossil-bearing limestones and shales.

From personal experience, I can recall few Paleozoic Era localities that have yielded such a profusion of excellent forms. Midwestern exposures certainly come to mind. While I was residing in eastern Kansas a number of years ago, I had the great fortune to explore several of the abandoned rock quarries in the area. These have penetrated late Pennsylvanian limestones and shales approximately 305 million years old, in which a mind-boggling diversity of beautiful specimens occur. One quarry just a few miles outside of town came to be my very favorite--the single finest Pennsylvanian Period fossil-bearing site from which I have ever collected.

If that quarry happens to rank as the best Pennsylvanian fossil locality, then there is no doubt that Fossil Mountain at Ibex is the finest Ordovician Period fossil-yielding area I have visited. It is true, of course, that I have yet to explore the famous Ohio Ordovician outcrops.

Although Fossil Mountain of Ibex lies within a proverbial no man's land--parched desert many miles from the nearest center of population (that would be Delta, Utah)--the fossil-bearing area is rather easily reached via a system of well-maintained dirt roads. Still, this no place to become stranded. Make certain that your vehicle is in perfect working order. Carry a well-maintained emergency first aid kit, extra food, and plenty of water: The traditional rule stresses that one must possess at least one gallon of water per person per day in reserve for the duration of an expected dry-camping expedition. And notify local authorities in Delta--or, Baker, Nevada, if one is traveling to Millard County from directions west--of your destination and how long you plan to stay. But be sure to contact them when returning to civilization, so they won't organize a rescue operation unnecessarily. While in the neighborhood of Baker in White Pine County, eastern Nevada, by the way, consider a visit to Great Basin National Park--established October 27, 1986; beaucoup scenic wilderness adventures await, and Baker Creek Campground at an elevation of roughly 7,500 feet makes a most comfortable base camp during summer visits.

Those of us who travel the desert regularly sometimes develop a lazy attitude toward these important reminders. I freely admit that I have on occasion broken the rules of safe and sane backroads travel conduct. Just call me lucky so far. So, don't do as I do--as the saying goes--do as I say.

Note, too, that Ibex's Fossil Mountain presently lies within the proposed King Top Wilderness area. This means that only surface collecting of fossil specimens is allowed--do not dig into the exposed strata; pick up and keep only what you find already lying atop the ground. And before proceeding into the wilds, check with the local Bureau of Land Management office (BLM) to determine the latest land status. If the region eventually goes the route of a federally protected wilderness, unauthorized amateur collectors will likely incur additional restrictions on their hobby fossil-finding activities. Obey all rules and regulations. For example, fossils collected on America's Public Lands (administered by the BLM) must never be sold or bartered--in legal argot, generally agreed by common convention to mean that you can't trade for specimens, either. Watch for BLM signs along the way that detail the latest official public lands status.

After negotiating a system of decently maintained dirt roads through several lonesome miles of classic Great Basin Desert terrain, one arrives at excellent exposures of the lower Ordovician Lehman Limestone--the first prominent and easily accessible outcrops of the paleontologically prolific Pogonip Group one encounters within view of looming Fossil Mountain, now less than two and a half miles away. The rugged slopes to the right of the dirt trail (north) consist of blue-gray-weathering arenaceous limestones in which moderately common brachiopods, ostracods (a small bean to pea-shaped bivalve crustacean), and gastropods occur. Yet another paleontological point is that the first corals in the local Ordovician Ibexian stratigraphic record happen to appear in the Lehman Limestone.

This is an advantageous place to become acquainted with the regional style of rock outcropping and fossil occurrences in the Fossil Mountain/Ibex District. You will note that the limestone layers here are essentially flat-lying, in what geologists call a horizontal bedding attitude. Considering the extreme geologic age of the Lehman Formation--some 470 million years old--the lack of metamorphism and related deformation of the Ordovician strata is absolutely astonishing.

The Lehman limestones tend to form prominent ledges, while the shale partings have been eroded back in recess. This is the distinctive geomorphological characteristic of all the exposed early Paleozoic rock formations in the Ibex District. Not every carbonate layer here is fossiliferous but, rather, the specimens occur in specific zones or horizons throughout the sequence. Some beds yield only ostracods, while others are packed with brachiopods, echinoderms, trilobites, or gastropods.

The Lehman Limestone is the youngest of the six geologic rock formations included in the geographically widespread lower Ordovician Pogonip Group--roughly 485 to 470 million years old--which reaches its most abundant and reliably diverse fossil development at Fossil Mountain and the surrounding Ibex area. In descending order of geologic age, this significant grouping of strata includes, first, the Lehman Limestone, then the Kanosh Shale, the Juab Limestone, the Wah Wah Limestone, the Fillmore Formation, and the House Limestone. In general, all Pogonip rocks but the House Limestone yield plentiful fossils. This is not to say that the House is a disappointing unit; it's just that its ledges of silicified trilobites are more difficult to spot in the field.

After examining the Lehman Limestone outcrops, one continues along the primary dirt road to another branching dirt trail. Which way to go to get to Fossil Mountain is now no longer even a question. At this point Fossil Mountain--the primary fossil-bearing locality in the Ibex District--looms to your immediate northwest, a great pyramid-shaped protuberance composed of a conformable (i.e., without any breaks in time in the geologic history of sedimentary deposition) sequence of lower Ordovician through middle Ordovician-age strata capped by the erosion-resistant middle Ordovician Eureka Quartzite (not a member of the Pogonip Group)--a massive accumulation of heat and pressure-altered sandstones that are in large part responsible for the protection of the fossiliferous limestones and shales below. They have prevented the erosion of the less-resistant Ordovician rocks in much the same manner that a small pebble resting atop a glob of mud will keep the mud mound intact through a rainstorm, while soil exposed to the brunt of the storm easily washes away.

Immediately below the brilliant white Eureka Quartzite capstone on Fossil Mountain are two additional rock formations geologists exclude from the early Ordovician Pogonip Group: The darker band below the quartzite peak is the middle Ordovician Crystal Peak Dolomite; and that bold, steep cliff face composed of alternating white and brown bands is the middle Ordovician Watson Ranch Quartzite, underlain in turn by a narrow, prominently protruding limestone ledge belonging to the lower Ordovician Lehman Limestone, the youngest member of the Pogonip Group. According to several official geological measurements, early to middle Ordovician-age rocks in Millard County accumulated to an aggregate thickness of some 3,500 feet.

At the intersection with the north-south trending dirt road that leads over to Fossil Mountain, you will note to the right of the road a magnificent exposure of the middle Ordovician Eureka Quartzite--the same geologic interval that caps Fossil Mountain. This is certainly one of the most widespread early Paleozoic Era rock units in all the Great Basin Desert. It has been recognized as far away as eastern California, in the mountains surrounding Death Valley National Park.

For decades, scientists have speculated on the original environment of deposition of the Eureka Quartzite, an unusually thick bed of heat and pressure-crushed sandstone. Many models have been analyzed, but no one explanation seems to answer all the questions.

The main problem for geologists is to satisfactorily account for such a massive, persistently uniform zone of practically pure metamorphosed sandstone that occurs over hundreds of square miles. It hasn't been easy. After much debate on the subject, earth scientists remain puzzled and intrigued, although recent investigations seem to show that the Eureka Quartzite accumulated some 465 million years ago as clean, well-sorted beach sand along the shores of a shallow sea during the middle portion of the Ordovician Period.

If this is true, the Eureka Quartzite could well represent one of the oldest identifiable terrestrial rock deposits in North American.

A short drive beyond the Eureka Quartzite exposure brings you directly in front of the place you want to visit.

Before you rises Fossil Mountain, one the great early Ordovician fossil-bearing sites in existence. It was named--and first popularly publicized--sometime between 1910 and 1920 by Frank Ashel Beckwith, a cashier at the first established bank in Delta, Utah, who spent considerable spare time exploring the fossil wonders of Millard County. Among a shipment of early Ordovician invertebrate fossils that Beckwith donated to the US National Museum (part of the Smithsonian Institution in Washington D.C.), a selection of brachiopods became the first paleontologic specimens from Fossil Mountain ever formally described in the scientific literature (1936 and 1938); mysteriously, though, the paleontologists who wrote up the papers failed to credit Beckwith as the donor.

A short walk toward Fossil Mountain will place you on the ledge-forming, dark-blue silty limestones of the Wah Wah Limestone. Silicified trilobites, algae-sponge patch reefs, conodonts (a minute feeding apparatus, unrelated to modern jaws, from an extinct eel-like organism--seen only in the insoluble residues of carbonates dissolved in a dilute solution of acetic or formic acid), graptolites, gastropods, brachiopods, solitary sponges, nautiloid cephalopods, and cystoid echinoderms constitute members of a large and diverse fossil assemblage.

The Wah Wah Limestone in the vicinity of Fossil Mountain is about 235 feet thick. It is traceable southward from the parking area for a little over a mile, and fossils can be collected throughout this entire area of outcrop.

As in the Lehman Limestone explored earlier, the Wah Wah specimens (yes, the Wah Wah is colloquially called "The George Harrison interval, where all things Ordovician must pass"...) tend to occur in distinct zones. This means that productive, fossiliferous horizons are separated by many feet of barren limestone and shales. The trick, naturally, is to locate these fossil-rich ledges, then follow them as they arc about the hillsides.

As you ascend the slopes of Fossil Mountain, the Wah Wah Limestone grades into the younger Juab Limestone, which consists mainly of medium-gray arenaceous limestone that forms ledges up to four feet thick. There are also minor interbeds of tan shale in the sequence.

Despite the fact that the Juab is a relatively thin geologic unit--only 160 feet at most--many fossil types are well-represented. Brachiopods, gastropods, cephalopods, trilobites, conodonts, solitary sponges, and graptolites are especially characteristic of the formation.

Directly above the Juab Limestone lies the next-youngest formation, which also happens to be the most fossiliferous lower Ordovician Pogonip Group unit of them all--the fabulous Kanosh Shale. Simply continue your hike upward along any of Fossil Mountain's numerous erosion gullies and you will soon intersect the unmistakable olive-brown to chocolate-brown shales that tend to form slopes and protruding ledges.

Here you will discover a profusion of fossils--especially orthid-type brachiopods which form beautiful museum-quality shell beds (also called monotypic beds); these are accumulations of prodigious quantities of a single species of brachiopod, only, that typically form a great percentage of the rocks in which they occur. Free-weathered brachiopods are abundant, as well--a superior selection of plentiful pedicle and brachial valves, plus fully articulated specimens with both valves preserved intact.

Researchers suggest that such Kanosh Shale monotypic shell beds developed under supremely stressful paleo-environmental conditions, probably when early Ordovician marine saline levels rose to critical concentrations, initiating "brachiopod blooms;" the brachs reacted to the increasingly intolerable alteration of a once-salubrious sea geochemistry with adaptive creativity; they opted to over-reproduce in sudden spurts, saturating the Ordovician sea floor with great numbers of their kind, ensuring that at least a few would persist and endure. On occasion, though, the periodic prolific brachiopod blooms were ultimately overcome by rapidly deteriorating conditions that proved fatal, and so entire beds composed mostly of their multitudinous valves built up on the sea floor.

Other fossil groups well represented in the Kanosh Shale include ostracods--which often form their own impressive monotypic shell beds--gastropods, bryozoans, cephalopods, pelecypods, graptolites, echinoderms, sponges, conodonts, and trilobites. Many Kanosh Shale bryozoans and echinoderms originally inhabited what paleontologists call hardgrounds: that is, sections of the Fossil Mountain sea floor created when early Ordovician storm waves exhumed abundant inorganically precipitated calcareous nodules, forming discrete, extensive beds of so-called "marine pavement." Upon these newly developed areas early echinoderms (often, a rhipidocystid eocrinoid) found a favorable environment to proliferate, contributing when they died vast numbers of disassociated ossicles (also called "stems" or columnals) and holdfasts--the minute, bulbous attachments that allowed the animals to anchor themselves--to the ever-thickening cemented substrate. Repeated echinoderm death cycles created ever-expanding space for an even more diverse echinoderm fauna to thrive, atop which, eventually, several species of bryozoans came along to help colonize the hardgrounds areas, as well--the first known bryozoans in the fossil record to inhabit hardgrounds, which are also known from the preceding Cambrian Period that ended some 10 million years before the Kanosh Shale began to accumulate, a time prior to 485 million years ago when only echinoderms contributed to hardground developments on the early Paleozoic sea floors. So scientificially fascinating are the Fossil Mountain examples that paleontologists and geologists from all around the world travel to Millard County, Utah, to study the classic Kanosh Shale hardgrounds.

This is a formation absolutely packed with wonderfully preserved fossil material. Like others before me, I could rave on and on about the excellence displayed here, the diversity of early Ordovician animal groups and the quality of their preservation, but you too will just have to see it to believe it. The Kanosh Shale, with its fantastic brachiopod and ostracod shell beds, early echinoderm-bryozoan hardground developments, and prolificly diverse free-weathered invertebrate animal fauna, ranks as one of the most important paleontologic exposures in North America. To collect here is an exhilarating, uplifting experience--one I will never forget.

The older Fillmore Formation and House Limestone are not exposed on the immediate slopes of Fossil Mountain, but typical fossiliferous outcrops can be found not far from the parking area. There, the Fillmore is roughly 1,600 feet thick, consisting of interbedded conglomerate, olive-gray to greenish shale, fine-grained limestone, and occasional lenticular algae-sponge patch reefs; other fossils present include graptolites, trilobites, brachiopods, conodonts, gastropods, echinoderms, and cephalopods. Oldest of the Pogonip Group formational subunits, the lowermost Ordovician House Limestone yields silicified trilobites and brachiopods through approximately the upper third of 500 feet of finely crystalline limestone in beds two to four feet thick.

My first visit to the Ibex District provided me with an extraordinary collection of early Ordovician invertebrate animal specimens. I only wish I could have stayed longer.

While exploring the gullies and dry washes at Fossil Mountain, I felt incredibly privileged to be collecting from such a remarkable series of fossil-bearing geologic formations. They were deposited some 485 to 470 million years ago in a warm shallow sea then situated astride the equator--a deep time tropical ocean that teemed with burgeoning early Paleozoic Era life. That varied life of the early Ordovician has now been preserved in splendid detail at Fossil Mountain, where neither the ravages of erosion nor the brute force of metamorphism has harmed the ancient animals. They now reside in the limestones and shales of a vanished age--kept alive in their death for nearly half a billion years, longer than the human mind can comprehend. The abundant and beautifully preserved fossils at Ibex give us a rare glimpse back in time to a unique association of animal life that will never exist again.

Images Of Fossils From Millard County, Utah

All photographs of fossils taken by author

Click on image for a larger picture. Trilobites of the genus-species Elrathia kingii from the Middle Cambrian Wheeler Shale, Wheeler Amphitheater, Millard County, Utah. The specimens are roughly 505 million years old.

Click on image for a larger picture. Trilobites of the genus-species Elrathia kingii from the Middle Cambrian Wheeler Shale, Wheeler Amphitheater, Millard County, Utah. The specimens are roughly 505 million years old.

Click on image for a larger picture. Trilobite of the genus-species Elrathia kingii from the Middle Cambrian Wheeler Shale, Wheeler Amphitheater, Millard County, Utah. The specimen is roughly 505 million years old.

Click on image for a larger picture. Trilobite of the genus-species Elrathia kingii from the Middle Cambrian Wheeler Shale, Wheeler Amphitheater, Millard County, Utah. The specimen is roughly 505 million years old.

Click on image for a larger picture. Trilobite of the genus-species Elrathia kingii from the Middle Cambrian Wheeler Shale, Wheeler Amphitheater, Millard County, Utah. The specimen is roughly 505 million years old.

Click on image for a larger picture. Trilobites of the genus-species Elrathia kingii from the Middle Cambrian Wheeler Shale, Wheeler Amphitheater, Millard County, Utah. The specimens are roughly 505 million years old. Photograph courtesy an individual who goes by the cyber-name "thez-yo," who collected the trilobites at the fee dig in 2015. A very representative selection of extraordinarily well preserved Elrathia trilobites one can expect to find in Wheelter Shale.

Click on image for a larger picture. Left to right--first two are pedicle valves of brachiopods; far right is a pedicle valve-view of a fully articulated brachiopod, with both pedicle and brachial valves preserved intact; genus-species is Shoshonorthis michaelis, from lower Ordovician Kanosh Shale, Fossil Mountain, Millard County, Utah. The specimens are approximately 475 million years old.

Click on image for a larger picture. Pedicle valves of brachiopods from the lower Ordovician Kanosh Shale, Fossil Mountain, Millard County, Utah. Genus-species is Shoshonorthis michaelis. The specimens are approximately 475 million years old.

Click on image for a larger picture. Brachiopods (primarily pedicle valves) of the genus-species Shoshonorthis michaelis from a shell bed in the lower Ordovician Kanosh Shale, Fossil Mountain, Millard County, Utah. The specimens are approximately 475 million years old.

Click on image for a larger picture. Brachiopods (primarily pedicle valves) of the genus-species Shoshonorthis michaelis from a shell bed in the lower Ordovician Kanosh Shale, Fossil Mountain, Millard County, Utah. The specimens are approximately 475 million years old.

Click on image for a larger picture. Bryozoans from the lower Ordovician Kanosh Shale, Fossil Mountain, Millard County, Utah. Kanoshopora sp. Identified by Dr. Mark A. Wilson, The College of Wooster. The specimens are approximately 475 million years old.

Click on image for a larger picture. A coiled gastropod from the lower Ordovician Lehman Limestone, Fossil Mountain, Millard County, Utah, of the family Macluritidae. The specimen is approximately 470 million years old.

Click on image for a larger picture. Ostracods, a bivalve crustacean (the small, black, bean to pea-shaped specimens), of the genus Leperditia sp. from the lower Ordovician Lehman Limestone, Fossil Mountain, Millard County, Utah. Twig-like specimen at lower left is a bryozoan colony. The specimens are approximately 470 million years old.

On-Site Images In Millard County, Utah

Click on the image for a larger picture. A panoramic view across the world-famous Wheeler Amphitheater trilobite beds. Here, a commercial fossil quarrying operation allows visitors to collect, for a reasonable fee, trilobites and other paleontologic specimens (including brachiopods, sponges, and echinoderms) in the middle Cambrian Wheeler Shale, approximately 505 million years old. Innumerable perfect, complete trilobites from this locality representing, primarily, a species called Elrathia kingii have found their way into museums and private collections all across the globe. All lighter-colored strata in foreground to middle-ground of photograph belong to the trilobite-rich Wheeler Shale. A Google Earth image I processed through photoshop.

Click on the image for a larger picture. A visitor explores the world-famous Wheeler Amphitheater trilobite beds, Millard County, Utah. Here, a commercial fossil quarrying operation allows visitors to collect, for a reasonable fee, trilobites and other paleontologic specimens (including brachiopods, sponges, and echinoderms) in the middle Cambrian Wheeler Shale, approximately 505 million years old. Innumerable perfect, complete trilobites from this locality representing, primarily, a species called Elrathia kingii have found their way into museums and private collections all across the globe.

Click on the image for a larger picture. A seeker of middle Cambrian paleontology splits shale in a commercial fossil dig operation at world-famous Wheeler Amphitheater, Millard County, Utah. The professionally excavated cut exposes extraordinarily fossiliferous middle Cambrian Wheeler Shale, approximately 505 million years old, within which innumerable perfect, complete trilobites occur--mainly a genus-species called Elrathia kingii.

Click on the image for a larger picture. A paleontology enthusiast examines a slab of trilobite-bearing shale at a commercial fossil dig in world-renowned Wheeler Amphitheater, Millard County, Utah. The fee-dig operators exposed the cut in left half of photograph in sedimentary rocks belonging to what geologists call the middle Cambrian Wheeler Shale, approximately 505 million years old. Plentiful whole, perfect trilobite carapaces can be recovered here by carefully splitting the shales along their natural planes of deposition with a rock hammer.

Click on the image for a larger picture. A visitor stands atop what's arguably the single most famous trilobite locality in the world--the middle Cambrian Wheeler Shale exposed in a commercial fee dig at Wheeler Amphitheater, Millard County, Utah. Exceptionally well preserved Elrathia kingii trilobites occur in abundance here within a two-foot thick section in the upper portions of the Wheeler Shale, below the overlying middle Cambrian Marjum Formation. The extinct 505 million year-old arthropods can be popped free, whole and intact, by gently tapping the shale matrix upon which they reside with a geology rock hammer.

Click on image for a larger view. Here is world-famous Fossil Mountain, Millard County, Utah, a profoundly important paleontological protuberance in the Great Basin Desert that exposes one of the great early Ordovician fossil-bearing rock sequences on the planet--a wildly fossiliferous accumulation of sedimentary material paleontologists and geologists alike call the Pogonip Group. This is a widespread association of six distinct rock formations roughly 485 to 470 million years old comprised of, in ascending order of geologic age (that is, oldest to youngest): the House Limestone; Fillmore Formation; Wah Wah Limestone; Juab Limestone; Kanosh Shale; and Lehman Limestone. Each Pogonip Group formational subunit yields unique suites of abundant invertebrate fossil specimens: trilobites, ostracods (bivalved crustacean), sponges, brachiopods, gastropods, pelecypods, cephalopods, graptolites, conodonts, echinoderms, corals and bryozoans, primarily, that often form shell beds composed of nothing but a single variety of fossil organism; for example, the Kanosh Shale is justifiably famous for its thick shell beds containing the prolific remains of a single species of brachiopod, called scientifically Shoshonorthis michaelis. Other beds produce abundant ostracods, gastropods, trilobites, or echinoderms, to the exclusion of all of other invertebrate animal types. Fossil Mountain in Millard County, Utah, could well yield the most diverse lower Ordovician fossil sequence in North America.

Although the House Limestone and Fillmore Formation do not occur at Fossil Mountain, proper, their abundantly fossiliferous limestones and shales can be examined at outcrops situated in the immediate vicinity of Fossil Mountain. Within the photograph, juniper trees along foreground to the base of Fossil Mountain grow atop the lower Ordovician Juab Limestone. Lowest erosion dissected slopes belong to the fabulous lower Ordovician Kanosh Shale, the most richly fossil-bearing member of the Pogonip Group. Directly above the Kanosh, at the first major erosion-resistant ledge along the cliff face, is the Lehman Limestone. Massive alternating brown and white rocks in the bold cliff above belong to the middle Ordovician Watson Ranch Quartzite. Uniformly darker band just below peak is the middle Ordovician Crystal Peak Dolomite. And capping Fossil Mountain is the lighter-colored, whitish, middle Ordovician Eureka Quartzite.

A still picture I cropped and processed through photoshop from a YouTube video lecture by Owen Nielsen of Great Basin Museum, published on July 31, 2014.

Click on image for a larger view of this photograph, in addition to the same view without lettering symbols. A seeker of Ordovician times explores the lower flanks of world-famous Fossil Mountain, Millard County, Utah. In the vast Great Basin Desert area immediately surrounding the paleontological protuberance occurs one of the great early Ordovician fossil-bearing rock sequences on the planet--a wildly fossiliferous accumulation of sedimentary material paleontologists and geologists alike call the Pogonip Group. This is a widespread association of six distinct rock formations roughly 485 to 470 million years old comprised of, in ascending order of geologic age (that is, oldest to youngest): the House Limestone; Fillmore Formation; Wah Wah Limestone; Juab Limestone; Kanosh Shale; and Lehman Limestone. Each Pogonip Group formational subunit yields unique suites of abundant invertebrate fossil specimens: trilobites, ostracods (bivalved crustacean), sponges, brachiopods, gastropods, pelecypods, cephalopods, graptolites, conodonts, echinoderms, corals, and bryozoans, primarily, that often form shell beds composed of nothing but a single variety of fossil organism; for example, the Kanosh Shale is justifiably famous for its thick shell beds containing the prolific remains of a single species of brachiopod, called scientifically Shoshonorthis michaelis. Other beds produce abundant ostracods, gastropods, trilobites, or echinoderms, to the exclusion of all of other invertebrate animal types. Fossil Mountain in Millard County, Utah, could well yield the most diverse lower Ordovician fossil sequence in North America.

The visitor is standing atop the lower Ordovician Juab Limestone (marked by the symbol Oj, in black). In ascending stratigraphic order (oldest to youngest), the succeeding lower to middle Ordovician geologic rock formations exposed on Fossil Mountain include: lower Ordovician Kanosh Shale (Ok); late lower Ordovician Lehman Limestone (Ol); middle Ordovician Watson Ranch Quartzite (Ow); middle Ordovician Crystal Peak Dolomite (Oc); and capping Fossil Mountain is the middle Ordovician Eureka Quartzite (Oe).

Click on the image for a larger picture. A view westward from an unnamed hill toward Fossil Mountain and the lower to late Ordovician rocks exposed immediately to the north. Symbols on photograph, from oldest to youngest exposures: "Kanosh" is the lower Ordovician Kanosh Shale (a member of the Pogonip Group); "Lehman"--lower Ordovician Lehman Limestone (youngest member of the Pogonip Group); "Watson Ranch"--middle Ordovician Watson Ranch Quartzite; "CP" is the middle Ordovician Crystal Peak Dolomite; "Eureka"--the middle Ordovician Eureka Quartzite (notice its increased thickness on the mountain immediately north of Fossil Mountain); and "Ely Springs" is the upper Ordovician Ely Springs Dolomite, known throughout eastern Nevada and western Utah for its abundant silificied corals and brachiopods, in particular. Note vehicle at lower left corner.

Among the lettered geologic rock formations, the lower Ordovician Kanosh Shale and Lehman Limestone produce prolific assemblages of brachiopods, ostracods (bivalved crustacean), sponges, trilobites, gastropods, pelcypods, cephalopods, graptolites, conodonts, echinoderms, corals, and bryozoans, primarily, that often form shell beds composed of nothing but a single variety of fossil organism; for example, the Kanosh Shale is justifiably famous for its thick shell beds containing the prolific remains of a single species of brachiopod, called scientifically Shoshonorthis michaelis. Other beds produce abundant ostracods, gastropods, trilobites, or echinoderms, to the exclusion of all of other invertebrate animal types. Fossil Mountain in Millard County, Utah, could well yield the most diverse lower Ordovician fossil sequence in North America.

I adapted and processed the photograph through photoshop from an image contained in the following publication: American Association of Petroleum Geologists Memoir 98, The Great American Carbonate Bank: The Geology and Economic Resources of the Cambrian-Ordovician Sauk Megasequence of Laurentia. Edited by James Derby, Richard Fritz, Susan Longacre, William Morgan, and Charles Sternbach. Published January 20, 2013.

Click on the image for a larger picture. A view slightly west of north near the base of Fossil Mountain (the slopes and cliff face at left of image) to the bold face of the mountain just to the north of Fossil Mountain, seen in the picture immediately preceding this one (at right side of that photograph). Fossil-bearing formations within this view include the lighter-colored strata along the lower slopes, composed of the lower Ordovician Kanosh Shale; and immediately above that, beginning at the first major, narrow, prominent ledge, and continuing up to the bold cliff face above, is the lower Ordovician Lehman Limestone. The lower Ordovician Kanosh Shale and Lehman Limestone produce prolific assemblages of brachiopods, ostracods (bivalved crustacean), sponges, trilobites, gastropods, pelcypods, cephalopods, graptolites, conodonts, echinoderms, corals, and bryozoans, primarily, that often form shell beds composed of nothing but a single variety of fossil organism; for example, the Kanosh Shale is justifiably famous for its thick shell beds containing the prolific remains of a single species of brachiopod, called scientifically Shoshonorthis michaelis. Other beds produce abundant ostracods, gastropods, trilobites, or echinoderms, to the exclusion of all of other invertebrate animal types. Fossil Mountain in Millard County, Utah, could well yield the most diverse lower Ordovician fossil sequence in North America. Image cropped and processed through photoshop from a photograph originally taken by an individual who goes by the cyber-moniker "rkahwoo."

Click on the image for a larger picture. A view northeast to the Ibex District from the slopes of Fossil Mountain; strata at right side of photograph belong to the lower Ordovician Kanosh Shale of the Pogonip Group, an association of six distinct geologic rock formations that produce prolific assemblages of brachiopods, ostracods (bivalved crustacean), sponges, trilobites, gastropods, pelcypods, cephalopods, graptolites, conodonts, echinoderms, corals, and bryozoans, primarily, that often form shell beds composed of nothing but a single variety of fossil organism; for example, the Kanosh Shale is justifiably famous for its thick shell beds containing the prolific remains of a single species of brachiopod, called scientifically Shoshonorthis michaelis. Other beds produce abundant ostracods, gastropods, trilobites, or echinoderms, to the exclusion of all of other invertebrate animal types. Fossil Mountain in Millard County, Utah, could well yield the most diverse lower Ordovician fossil sequence in North America. Image cropped and processed through photoshop from a photograph originally taken by an individual who goes by the cyber-moniker "traprock1."

Click on the image for a larger view. Here's a panorama to the southern end of the Barn Hills, depicting the exact spot for which the world-famous Ibex District was named--a regional Millard County locale that also includes incomparable Fossil Mountain; the white lettering "IBEX" is the site originally named for a European wild goat by English immigrant Jack Watson, who established a post office there in the 1890s on property he homesteaded. The green "brushes" in lower part of image are in fact juniper trees. Geologic rock formations in view include the middle Ordovician Eureka Quartzite and the upper Ordovician Ely Springs Dolomite, which yields many silicified corals and brachiopods.

I adapted and processed the photograph through photoshop from an image contained in the following publication: American Association of Petroleum Geologists Memoir 98, The Great American Carbonate Bank: The Geology and Economic Resources of the Cambrian-Ordovician Sauk Megasequence of Laurentia. Edited by James Derby, Richard Fritz, Susan Longacre, William Morgan, and Charles Sternbach. Published January 20, 2013.

Images From Great Basin National Park, Nevada

Click on the image for a larger picuture. A view southwestward in Baker, White Pine County, Nevada, along State Route 487 near the intersection with SR 488--the turnoff to Great Basin National Park situated five miles west. The town is named after an early settler, George W. Baker. A still image I cropped and processed through photoshop from a video about Baker, Nevada, and neighboring Great Basin National Park, published to YouTube by "2012escapee1" on October 20, 2014.

Click on the image for a larger picture. A view in Great Basin National Park, White Pine County, Nevada, to: Wheeler Peak--elevation 13,063 feet (second-highest peak in Nevada); Wheeler Peak Glacier (roughly center of image); and the Wheeler glacial moraine. A still picture I cropped and processed through photoshop from a video about Great Basin National Park, produced by the National Park Service.

Click on the image for a larger picture. A view southward from the summit of Wheeler Peak--elevation 13,063 feet (second-highest peak in Nevada) in Great Basin National Park, White Pine County, Nevada. A picture I cropped and processed through photoshop from an image originally taken and uploaded to Google Earth by an individual named Ryan Weidert.

Click on the image for a larger view. A deer observed during a drive through Great Basin National Park, White Pine County, eastern Nevada--a locality that makes an excellent side-trip while exploring the world-class paleontology of nearby Millard County, Utah; an early Fall scene.

Click on the image for a larger picture. An ancient Great Basin Bristlecone Pine (Pinus longaeva) in Great Basin National Park, White Pine County, Nevada--the oldest continuously living, non-cloning thing on earth; one Bristlecone Pine has lived over 5,000 years, and several have survived beyond 4,000 years. Note of course that "families" (groups) of trees that reproduce by cloning can live much longer. For example, a colony of 47,000 quaking aspens in Utah is around 80,000 years old, even though the average age of the individual aspens in only 130 years. A still picture I cropped and processed through photoshop from a video about Bristocone Pines, produced by the National Park Service.

Click on the image for a larger picture. View is northwest along a paved road through Great Basin National Park, White Pine County, eastern Nevada. A Google Earth street car image I cropped and processed through photoshop. Image originally snapped sometime in the month of September. Elevation at this point is 6,858 feet.

Click on the image for a larger picture. A visitor to Great Basin National Park explores Lehman Caves during one of the regularly scheduled tours--one of 40 caves known to exist within the park, but the only one open to the public. The National Park Service notes that the caves were probably discovered by Absalom Lehman in 1885. A still picture I cropped and processed through photoshop from a video about Great Basin National Park, produced by the National Park Service.

Click on the image for a larger picture. Cave formations at Lehman Caves in Great Basin National Park--one of 40 caves known to exist within the park, but the only one open to the public. The National Park Service notes that the caves were probably discovered by Absalom Lehman in 1885. A still picture I cropped and processed through photoshop from a video about Great Basin National Park, produced by the National Park Service.

Click on the image for a larger picture. A panorama looking eastward at a pullout on the way to Wheeler Peak in Great Basin National Park, White Pine County, Nevada. Elevation here is roughly 8,000 feet. A still image I cropped and processed through photoshop from a video about Baker, Nevada, and neighboring Great Basin National Park, published to YouTube by "2012escapee1" on October 20, 2014.

Click on the image for a larger picture. A view across Baker Creek Campground, site #16--elevation roughly 7,500 feet--in Great Basin National Park, White Pine County, eastern Nevada; an early Fall scene. Great Basin National Park makes a superior side-trip while exploring the abundant paleontological wonders of nearby Millard County, Utah.

Click on the image for a larger picture. Two very happy campers--my late parents--at Baker Creek Campground, site #16, in Great Basin National Park, White Pine County, eastern Nevada; photograph taken September 26, 1989. Elevation is roughly 7,500 feet. Great Basin National Park was established on October 27, 1986.

My Other Web Sites

  • The Acoustic Guitar Solitaire Of Inyo: A Cyber-CD: Listen to me play 30 covers of some of my favorite songs on an acoustic 6-string guitar; it's all free music.
  • Beyond The Timberline--A Cyber-CD: Listen to me play 32 selections comprised of covers and original tunes on acoustic 6 and 12-string guitars; it's all free music.
  • The Distant Path--A Cyber-CD: Listen to me play 32 acoustic guitar covers and original compositions; it's all free music.
  • Inyo And Folks--A Musical History--A Cyber-CD: My parents and I play 110; it's all free music.
  • Acoustic Stratigraphy--A Cyber-CD: Listen to me play 34 covers of some of my favorite songs on 6 and 12-string guitars; it's all free music.
  • Back To Badwater--A Cyber-CD: Listen to me play 32 covers and original compositions on 6 and 12-string guitars; it's all free music.
  • For an all-text page that includes all 332 of my guitar mp3 files placed on the Internet, go to All Inyo All The Time. That's where you'll find access to all of my musical selections, in order of their appearance on the Web--from my first Cyber-CD ("The Acoustic Guitar Solitaire Of Inyo") to the last, "The Rarities And Alternate Recordings Of Inyo."
  • Inyo 7--A Cyber CD: Listen to me play 30 covers of some of my favorite songs, plus originals (all free music).
  • The Rarities And Alternate Recordings Of Inyo--A Cyber-CD Listen to me play 32 seldom-heard, rare, alternate recordings of some of my previously released tracks.
  • Jump on over to my page It's A Happening Thing--Music From The Year 1967. Includes YouTube (and other sources) links to all songs that charted US Billboard Top 100 in year 1967 (close to a thousand, as as matter of fact), plus links to records that bubbled under US Billboard's Hot 100 charts that year (releases that placed #101 to #135); peruse, too, my extensive personal database of year 1967 music.

Paleontology-Related Pages

Web sites I have created pertaining to fossils

  • Fossils In Death Valley National Park: A site dedicated to the paleontology, geology, and natural wonders of Death Valley National Park; lots of on-site photographs of scenic localities within the park; images of fossils specimens; links to many virtual field trips of fossil-bearing interest.
  • Fossil Insects And Vertebrates On The Mojave Desert, California: Journey to two world-famous fossil sites in the middle Miocene Barstow Formation: one locality yields upwards of 50 species of fully three-dimensional, silicified freshwater insects, arachnids, and crustaceans that can be dissolved free and intact from calcareous concretions; a second Barstow Formation district provides vertebrate paleontologists with one of the greatest concentrations of Miocene mammal fossils yet recovered from North America--it's the type locality for the Bartovian State of the Miocene Epoch, 15.9 to 12.5 million years ago, with which all geologically time-equivalent rocks in North American are compared.
  • A Visit To Fossil Valley, Great Basin Desert, Nevada: Take a virtual field trip to a Nevada locality that yields the most complete, diverse, fossil assemblage of terrestrial Miocene plants and animals known from North America--and perhaps the world, as well.
  • Fossils At Red Rock Canyon State Park, California: Visit wildly colorful Red Rock Canyon State Park on California's northern Mojave Desert, approximately 130 miles north of Los Angeles--scene of innumerable Hollywood film productions and commercials over the years--where the Middle to Late Miocene (13 to 7 million years old) Dove Spring Formation, along with a classic deposit of petrified woods, yields one of the great terrestrial, land-deposited Miocene vertebrate fossil faunas in all the western United States.
  • Late Pennsylvanian Fossils In Kansas: Travel to the midwestern plains to discover the classic late Pennsylvanian fossil wealth of Kansas--abundant, supremely well-preserved associations of such invertebrate animals as brachiopods, bryozoans, corals, echinoderms, fusulinids, mollusks (gastropods, pelecypods, cephalopods, scaphopods), and sponges; one of the great places on the planet to find fossils some 307 to 299 million years old.
  • Fossil Plants Of The Ione Basin, California: Head to Amador County in the western foothills of California's Sierra Nevada to explore the fossil leaf-bearing Middle Eocene Ione Formation of the Ione Basin. This is a completely undescribed fossil flora from a geologically fascinating district that produces not only paleobotanically invaluable suites of fossil leaves, but also world-renowned commercial deposits of silica sand, high-grade kaolinite clay and the extraordinarily rare Montan Wax-rich lignites (a type of low grade coal).
  • Trilobites In The Marble Mountains, Mojave Desert, California: Take a trip to the place that first inspired my life-long fascination and interest in fossils--the classic trilobite quarry in the Lower Cambrian Latham Shale, in the Marble Mountains of California's Mojave Desert. It's a special place, now included in the rather recently established Trilobite Wilderness, where some 21 species of ancient plants and animals have been found--including trilobites, an echinoderm, a coelenterate, mollusks, blue-green algae and brachiopods.
  • Early Cambrian Fossils Of Westgard Pass, California: Visit the Westgard Pass area, a world-renowned geologic wonderland several miles east of Big Pine, California, in the neighboring White-Inyo Mountains, to examine one of the best places in the world to find archaeocyathids--an enigmatic invertebrate animal that went extinct some 510 million years ago, never surviving past the early Cambrian; also present there in rocks over a half billion years old are locally common trilobites, plus annelid and arthropod trails, and early echinoderms.
  • Paleozoic Era Fossils At Mazourka Canyon, Inyo County, California: Visit a productive Paleozoic Era fossil-bearing area near Independence, California--along the east side of California's Owens Valley, with the great Sierra Nevada as a dramatic backdrop--a paleontologically fascinating place that yields a great assortment of invertebrate animals.
  • A Visit To Ammonite Canyon, Nevada: Explore one of the best-exposed, most complete fossiliferous marine late Triassic through early Jurassic geologic sections in the world--a place where the important end-time Triassic mass extinction has been preserved in the paleontological record. Lots of key species of ammonites, brachiopods, corals, gastropods and pelecypods.
  • Late Triassic Ichthyosaur And Invertebrate Fossils In Nevada: Journey to two classic, world-famous fossil localities in the Upper Triassic Luning Formation of Nevada--Berlin-Ichthyosaur State Park and Coral Reef Canyon. At Berlin-Ichthyosaur, observe in-situ the remains of several gigantic ichthyosaur skeletons preserved in a fossil quarry; then head out into the hills, outside the state park, to find plentiful pelecypods, gastropods, brachiopods and ammonoids. At Coral Reef Canyon, find an amazing abundance of corals, sponges, brachiopods, echinoids (sea urchins), pelecypods, gastropods, belemnites and ammonoids.
  • Fossils From The Kettleman Hills, California: Visit one of California's premiere Pliocene-age (approximately 4.5 to 2.0 million years old) fossil localities--the Kettleman Hills, which lie along the western edge of California's Great Central Valley northwest of Bakersfield. This is where innumerable sand dollars, pectens, oysters, gastropods, "bulbous fish growths" and pelecypods occur in the Etchegoin, San Joaquin and Tulare Formations.
  • Field Trip To The Kettleman Hills Fossil District, California: Take a virtual field trip to a classic site on the western side of California's Great Central Valley, roughly 80 miles northwest of Bakersfield, where several Pliocene-age (roughly 4.5 to 2 million years old) geologic rock formations yield a wealth of diverse, abundant fossil material--sand dollars, scallop shells, oysters, gastropods and "bulbous fish growths" (fossil bony tumors--found nowhere else, save the Kettleman Hills), among many other paleontological remains.
  • A Visit To The Sharktooth Hill Bone Bed, Southern California: Travel to the dusty hills near Bakersfield, California, along the eastern side of the Great Central Valley in the western foothills of the Sierra Nevada, to explore the world-famous Sharktooth Hill Bone Bed, a Middle Miocene marine deposit some 16 to 15 million years old that yields over a hundred species of sharks, rays, bony fishes, and sea mammals from a geologic rock formation called the Round Mountain Silt Member of the Temblor Formation; this is the most prolific marine, vertebrate fossil-bearing Middle Miocene deposit in the world.
  • In Search Of Fossils In The Tin Mountain Limestone, California: Journey to the Death Valley area of Inyo County, California, to explore the highly fossiliferous Lower Mississippian Tin Mountain Limestone; visit three localities that provide easy access to a roughly 358 million year-old calcium carbate accumulation that contains well preserved corals, brachiopods, bryozoans, crinoids, and ostracods--among other major groups of invertebrate animals.
  • Middle Triassic Ammonoids From Nevada: Travel to a world-famous fossil locality in the Great Basin Desert of Nevada, a specific place that yields some 41 species of ammonoids, in addition to five species of pelecypods and four varieties of belemnites from the Middle Triassic Prida Formation, which is roughly 235 million years old; many paleontologists consider this specific site the single best Middle Triassic, late Anisian Stage ammonoid locality in the world. All told, the Prida Formation yields 68 species of ammonoids spanning the entire Middle Triassic age, or roughly 241 to 227 million years ago.
  • Fossil Bones In The Coso Range, Inyo County, California: Visit the Coso Range Wilderness, west of Death Valley National Park at the southern end of California's Owens Valley, where vertebrate fossils some 4.8 to 3.0 million years old can be observed in the Pliocene-age Coso Formation: It's a paleontologically significant place that yields many species of mammals, including the remains of Equus simplicidens, the Hagerman Horse, named for its spectacular occurrences at Hagerman Fossil Beds National Monument in Idaho; Equus simplicidens is considered the earliest known member of the genus Equus, which includes the modern horse and all other equids.
  • Field Trip To A Vertebrate Fossil Locality In The Coso Range, California: Take a cyber-visit to the famous bone-bearing Pliocene Coso Formation, Coso Mountains, Inyo County, California; includes detailed text for the field trip, plus on-site images and photographs of vertebrate fossils.
  • Fossil Plants At Aldrich Hill, Western Nevada: Take a field trip to western Nevada, in the vicinity of Yerington, to famous Aldrich Hill, where one can collect some 35 species of ancient plants--leaves, seeds and twigs--from the Middle Miocene Aldirch Station Formation, roughly 12 to 13 million years old. Find the leaves of evergreen live oak, willow, and Catalina Ironwood (which today is restricted in its natural habitat solely to the Channel Islands off the coast of Southern California), among others, plus the seeds of many kinds of conifers, including spruce; expect to find the twigs of Giant Sequoias, too.
  • Fossils From Pleistocene Lake Manix, California: Explore the badlands of the Manix Lake Beds on California's Mojave Desert, an Upper Pleistocene deposit that produces abundant fossil remains from the silts and sands left behind by a great fresh water lake, roughly 350,000 to 19,000 years old--the Manix Beds yield many species of fresh water mollusks (gastropods and pelecypods), skeletal elements from fish (the Tui Mojave Chub and Three-Spine Stickleback), plus roughly 50 species of mammals and birds, many of which can also be found in the incredible, world-famous La Brea Tar Pits of Los Angeles.
  • Field Trip To Pleistocene Lake Manix, California: Go on a virtual field trip to the classic, fossiliferous badlands carved in the Upper Pleistocene Manix Formation, Mojave Desert, California. It's a special place that yields beaucoup fossil remains, including fresh water mollusks, fish (the Mojave Tui Chub), birds and mammals.
  • Trilobites In The Nopah Range, Inyo County, California: Travel to a locality well outside the boundaries of Death Valley National Park to collect trilobites in the Lower Cambrian Pyramid Shale Member of the Carrara Formation.
  • Ammonoids At Union Wash, California: Explore ammonoid-rich Union Wash near Lone Pine, California, in the shadows of Mount Whitney, the highest point in the contiguous United States. Union Wash is a ne plus ultra place to find Early Triassic ammonoids in California. The extinct cephalopods occur in abundance in the Lower Triassic Union Wash Formation, with the dramatic back-drop of the glacier-gouged Sierra Nevada skyline in view to the immediate west.
  • A Visit To The Fossil Beds At Union Wash, Inyo County California: A virtual field trip to the fabulous ammonoid accumulations in the Lower Triassic Union Wash Formation, Inyo County, California--situated in the shadows of Mount Whitney, the highest point in the contiguous United States.
  • Ordovician Fossils At The Great Beatty Mudmound, Nevada: Visit a classic 475-million-year-old fossil locality in the vicinity of Beatty, Nevada, only a few miles east of Death Valley National Park; here, the fossils occur in the Middle Ordovician Antelope Valley Limestone at a prominent Mudmound/Biohern. Lots of fossils can be found there, including silicified brachiopods, trilobites, nautiloids, echinoderms, bryozoans, ostracodes and conodonts.
  • Paleobotanical Field Trip To The Sailor Flat Hydraulic Gold Mine, California: Journey on a day of paleobotanical discovery with the FarWest Science Foundation to the western foothills of the Sierra Nevada--to famous Sailor Flat, an abandoned hydraulic gold mine of the mid to late 1800s, where members of the foundation collect fossil leaves from the "chocolate" shales of the Middle Eocene auriferous gravels; all significant specimens go to the archival paleobotanical collections at the University California Museum Of Paleontology in Berkeley.
  • Early Cambrian Fossils In Western Nevada: Explore a 518-million-year-old fossil locality several miles north of Death Valley National Park, in Esmeralda County, Nevada, where the Lower Cambrian Harkless Formation yields the largest single assemblage of Early Cambrian trilobites yet described from a specific fossil locality in North America; the locality also yields archeocyathids (an extinct sponge), plus salterella (the "ice-cream cone fossil"--an extinct conical animal placed into its own unique phylum, called Agmata), brachiopods and invertebrate tracks and trails.
  • Fossil Leaves And Seeds In West-Central Nevada: Take a field trip to the Middlegate Hills area in west-central Nevada. It's a place where the Middle Miocene Middlegate Formation provides paleobotany enthusiasts with some 64 species of fossil plant remains, including the leaves of evergreen live oak, tanbark oak, bigleaf maple, and paper birch--plus the twigs of giant sequoias and the winged seeds from a spruce.
  • Ordovician Fossils In The Toquima Range, Nevada: Explore the Toquima Range in central Nevada--a locality that yields abundant graptolites in the Lower to Middle Ordovician Vinini Formation, plus a diverse fauna of brachiopods, sponges, bryozoans, echinoderms and ostracodes from the Middle Ordovician Antelope Valley Limestone.
  • Fossil Plants In The Dead Camel Range, Nevada: Visit a remote site in the vicinity of Fallon, Nevada, where the Middle Miocene Desert Peak Formation provides paleobotany enthusiasts with 22 species of nicely preserved leaves from a variety of deciduous trees and evergreen live oaks, in addition to samaras (winged seeds), needles and twigs from several types of conifers.
  • Early Triassic Ammonoid Fossils In Nevada: Visit the two remote localities in Nevada that yield abundant, well-preserved ammonoids in the Lower Triassic Thaynes Formation, some 240 million years old--one of the sites just happens to be the single finest Early Triassic ammonoid locality in North America.
  • Fossil Plants At Buffalo Canyon, Nevada: Explore the wilds of west-central Nevada, a number of miles from Fallon, where the Middle Miocene Buffalo Canyon Formation yields to seekers of paleontology some 54 species of deciduous and coniferous varieties of 15-million-year-old leaves, seeds and twigs from such varieties as spruce, fir, pine, ash, maple, zelkova, willow and evergreen live oak
  • High Inyo Mountains Fossils, California: Take a ride to the crest of the High Inyo Mountains to find abundant ammonoids and pelecypods--plus, some shark teeth and terrestrial plants in the Upper Mississippian Chainman Shale, roughly 325 million years old.
  • Field Trip To The Copper Basin Fossil Flora, Nevada: Visit a remote region in Nevada, where the Late Eocene Dead Horse Tuff provides seekers of paleobotany with some 42 species of ancient plants, roughly 39 to 40 million years old, including the leaves of alder, tanbark oak, Oregon grape and sassafras.
  • Fossil Plants And Insects At Bull Run, Nevada: Head into the deep backcountry of Nevada to collect fossils from the famous Late Eocene Chicken Creek Formation, which yields, in addition to abundant fossil fly larvae, a paleobotanically wonderful association of winged seeds and fascicles (bundles of needles) from many species of conifers, including fir, pine, spruce, larch, hemlock and cypress. The plants are some 37 million old and represent an essentially pure montane conifer forest, one of the very few such fossil occurrences in the Tertiary Period of the United States.
  • A Visit To The Early Cambrian Waucoba Spring Geologic Section, California: Journey to the northwestern sector of Death Valley National Park to explore the classic, world-famous Waucoba Spring Early Cambrian geologic section, first described by the pioneering paleontologist C.D. Walcott in the late 1800s; surprisingly well preserved 540-510 million-year-old remains of trilobites, invertebrate tracks and trails, Girvanella algal oncolites and archeocyathids (an extinct variety of sponge) can be observed in situ.
  • Petrified Wood From The Shinarump Conglomerate: An image of a chunk of petrified wood I collected from the Upper Triassic Shinarump Conglomerate, outside of Dinosaur National Monument, Colorado.
  • Fossil Giant Sequoia Foliage From Nevada: Images of the youngest fossil foliage from a giant sequoia ever discovered in the geologic record--the specimen is Lower Pliocene in geologic age, around 5 million years old.
  • Some Favorite Fossil Brachiopods Of Mine: Images of several fossil brachiopods I have collected over the years from Paleozoic, Mesozoic and Cenozoic-age rocks.
  • For information on what can and cannot be collected legally from America's Public Lands, take a look at Fossils On America's Public Lands and Collecting On Public Lands--brochures that the Bureau Of Land Management has allowed me to transcribe.
  • In Search Of Vanished Ages--Field Trips To Fossil Localities In California, Nevada, And Utah--My fossils-related field trips in full print book form (pdf). 98,703 words (equivalent to a medium-size hard cover work of non-fiction); 250 printed pages (equivalent to about 380 pages in hard cover book form); 27 chapters; 30 individual field trips to places of paleontological interest; 60 photographs--representative on-site images and pictures of fossils from each locality visited.

United States Geological Survey Papers (Public Domain)

Online versions of USGS publications

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