| The view is roughly northwest across a significant geologic exposure of Ordovician Period strata mear Mazourka Canyon, Inyo County, California. Lettering on photograph denotes the individual geologic rock formations that occur in conformable sequence--that is, there were no appreciable breaks in sedimentary deposition here during Ordovician times. From right to left, oldest to youngest: Obf is the middle Ordovician Badger Flat Limestone (produces gastropods, brachiopods, cystoid echinoderms, and trilobites); Obsl and Obsu designate the lower and upper members, respectively, of the late middle Ordovician Barrel Spring Limestone (yields brachiopods, graptolites, and trilobites); to the immediate left of the Barrel Spring Formation is a complete section of the late middle Ordovician Johnson Spring Formation (contains corals, brachiopods, sponges, crinoids, bryozoans, cephalopods, conodonts, and gastropods. |