High Inyo Mountains Fossils

Find 325 million year-old fossils near the crest of the Inyo Mountains, California

Contents For: High Inyo Mountains Fossils

Text: The Field Trip Images: On-Site Images: Fossils   Wigdet: Keeler Weather

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The view from the crest of California's Inyo Mountains, near the Upper Mississippian Chainman Shale ammonoid locality, includes spectacular panoramas of the Sierra Nevada. Mount Whitney, the highest point in the contiguous United States at 14,495', is the peak just left of center along the Sierran skyline--a small white cloud touches its tip. Strata in the foreground include the Upper Mississippian Chainman Shale, which yields many species of ammonoids and pelecypods, in addition to terrestrial plants and even shark teeth at a unique fossil locality that lies in the vicinity of the old ghost town of Cerro Gordo, Inyo County, California.

The Field Trip

An unusual fossil locality occurs east of Owens Lake, near the crest of California's Inyo Mountains--a place many fossil enthusiasts call the Chainman Shale site, where 325-million-year-old ammonoids can be found along the same bedding planes that yield fossil shark teeth and terrestrial plants. The paleontological remains have been preserved in what geologists refer to as the Upper Mississippian Chainman Shale, a thick marine deposit, almost everywhere slightly metamorphosed--a geographically widespread rock unit (its type locality is over in eastern Nevada) that also contains several species of pelecypods and brachiopods, in addition to a peculiar orthocone nautiloid cephalopod called Bactrites, or in more colloquial language the "darning needle" cephalopod because of its sharply elongated, needle-like appearance in the rocks.

The Inyo Mountains fossil horizon lies in the vicinity of Cerro Gordo, an abandoned mining camp that produced beaucoup spondulix worth of silver, lead, and zinc during the latter half of the 1800s (that would be many millions of dollars). It is now a picturesque ghost town preserved in what is euphemistically termed a state of "arrested decay." Years ago, before the question of legal ownership of the property had been settled, the multi-hued pulverulent mine tailings surrounding the town used to furnish collectors with such relatively uncommon mineral varieties as caledonite (a copper-lead sulfate), linarite (lead-copper sulfate), and leadhillite (a lead-sulfate-carbonate), in addition to excellent examples of smithsonite (a zinc carbonate) that often rivaled specimens from the famous Kelly Mine in New Mexico. But those days are now a distant memory in the minds of older mineral enthusiasts. Today, every last square inch of Cerro Gordo is privately owned, and mineral collecting within its posted boundaries is strictly forbidden without the owners' prior approval. For details about how to secure a permit to collect mineral specimens at Cerro Gordo, contact the regional office of the Bureau of Land Management in Ridgecrest, California. In the past, though, only "fully accredited individuals" have had success in finagling the essential legal documentation.

Not only is the Cerro Gordo fossil district a productive and scenic area to explore, it is also a place of great paleontological importance. As one of only three known Carboniferous (the European equivalent of the Mississippian and Pennsylvanian Periods combined) ammonoid localities in all of California, it is also the only such example currently accessible to amateur fossil buffs. The other two occur in Death Valley National Park (officially established in 1994), near the famous Racetrack in the northern sector of the vast park--now, with the assimilation of many thousands of acres of adjacent wilderness lands, larger than the entire state of Connecticut--where rocks of varying shapes and sizes apparently slide in mysterious secrecy across a wide desert playa. The long-held traditional explanation was that during winter, with nobody around to see the phenomena occur, preferably in the dead of night, fierce wind gusts--upwards of 100 miles per hour--pushed the rocks across slippery playa muds saturated by rare episodes of Death Valley precipitation; a "definitive" explanation, though, is that on occasion ice sheets form around the Racetrack stones, creating minature "rafts" that proceed to transport the rocks across the wet playa when bumped by a neighboring ice sheet whose motion in turn is initiated by gusts of wind.

In actual fact, both Death Valley sites are extensions of a single phenomenally productive cephalopod-bearing horizon in the Upper Mississippian Perdido Formation. Each yields innumerable ammonoids that characteristically weather out whole and intact, although many of the cephalopodic remains reveal obvious signs of degradation to their exteriors caused by the ceaseless abrasive weathering in the harsh transitional Mojave Desert-Great Basin Desert elements. Even so, numerous specimens still retain their original suture lines--that is, the distinctive growth line of the junction of a cephalopod's shell with the inner surface of its shell wall, which paleontologists use to identify the genus and species of all shell-bearing cephalopods, both living and extinct.

Even though the Cerro Gordo locality fails to yield free-weathering specimens, its ammonoids and associated brachiopods, pelecypods, terrestrial plants and shark teeth are, nevertheless, common to abundant in the slightly metamorphosed detrital deposits of the Upper Mississippian Chainman Shale. They are preserved as attractive reddish-brown limonitic casts and molds of the original 325-million-year-old organisms, set on a matrix of pale-to medium-gray slaty shale. The majority of ammonoid specimens are rather diminutive, with diameters of generally 10 millimeters or less. So, be sure to carry with you a good-quality magnifying glass. Their preservation is fair to excellent--very surprising when you consider the degree of metamorphism the matrix was unavoidably subjected to in the geologic past. When the Sierra Nevada began to buckle upward during the late Jurassic Period, many relatively incompetent shale beds in the Inyo Range underwent moderate to severe alteration. That the ammonoids and associated goodies in the Chainman Shale escaped this ravaging assault was indeed a miraculous occurrence.

Prior to their having survived obliteration by powerful geologic processes, the Chainman Shale organisms were deposited at the muddy bottom of a rather deep, warm-water Paleozoic sea some 325 million years ago. Now they lie at elevations of 8,800 to 9,000 feet near the crest of the great Inyo Range near Cerro Gordo ghost town. The ride up to the site, along the precipitous western flanks of the Inyo Range, is a hair-raising adventure. The jeep trail climbs over a mile in a mere seven or eight miles...although the vast majority of that amazing ascent takes place within a distance of only three or four miles. Needless to say, only those with a reliable four-wheel-drive vehicle should consider accepting the challenge.

It doesn't hurt to be in at least moderate physical condition, either. Once within striking distance of the fossil ammonoids and shark teeth, you will have to hike at elevations approaching 9,000 feet. For those unaccustomed to exertion at high altitudes, serious consequences can result--not the least of which is altitude sickness, a debilitating condition caused by prolonged oxygen depravation.

The turnoff to the Chainman Shale fossil bonanza lies along the eastern side of Owens Lake--an essentially dry saline depression most of the year (occasional heavy runoff from the mountains during Spring sometimes results in a big shallow pond that evaporates quickly)--near Keeler, where Cerro Gordo Road intersects State Route 136 13.5 miles southeast of Highway 395. Check your pulse at this point and get a grip!

The adventure begins at a modest 3,800 feet or so, with billows of irritating saline dust rising from "Owens Lake." Within just a few miles (when hairpin turns spiral upward and upward), you might reconsider having stayed behind in what had previously seemed the inhospitable Owens Lake below, and even find yourself obsessing on the flatness of it--that wonderful level expanse with no sheer drop-offs on either side.

Turn east on Cerro Gordo Road. Here you leave civilization behind. You will be striking though a great wilderness: a geological wonderland comprised of thick geologic rock deposits, in which many kinds of Paleozoic Era fossil remains can be recovered. Mainly these include fusulinids, brachiopods, corals, bryozoans, and crinoid fragments from the middle Pennsylvanian Keeler Canyon Formation and the Lower Permian Owens Valley Group. Also exposed in the area surrounding Cerro Gordo is the Lower Mississippian Tin Mountain Limestone (350 million years old)--a noted producer of corals and crinoids in particular from massive reef-like carbonate accumulations in its youngest phases of sedimentary deposition.

During the first 2.2 miles of four-wheel drive travel, you pass through Pleistocene (present official calibration--2,588,000 to 11,700 years ago) to recent fanglomerate--extensive accumulations of eroded debris from every sedimentary and volcanic outcrop in the Inyo Mountains. Limestone cobbles in the alluvial material sometimes contain abundant fusulinid tests; however, because the host deposit consists of weathered rock out of its normal stratigraphic position, the best that can be said regarding its geologic age is that any fusulinid found within it probably came from either the Keeler Canyon Formation or the Owens Valley Group. These are the only rock units in the Inyo complex known to contain the distinctive wheat-shaped test secreted by an extinct single-celled animal.

At 2.2 miles from State Route 136, Cerro Gordo Road begins to slice through the Lower Permian Owens Valley Group, which is roughly 285 million years old. Here, the Owens Valley is composed of several sedimentary lithologies, including silty fusulinid-bearing limestone, lenticular organic limestone (within which brachiopods, corals, crinoids and bryozoans can be found), calcareous shales, sandy limestone, limestone-mud breccias, and relatively pure limestones. Fossil remains are not abundant in the Owens Valley exposures along Cerro Gordo Road. But farther southeast, in the Darwin District of Inyo County, profuse fusulinids, brachiopods, and corals have been reported.

For 1.4 miles Cerro Gordo Road passes through dramatic exposures of the Lower Permian Owens Valley Group. Then it intersects an unnamed terrestrial accumulation of Middle Triassic (220 million-year-old) volcanics and sedimentary rocks approximately 2,200 feet thick. The volcanic facies includes andesite flows, breccia and tuffs of gray, red and purple; among the sedimentary constituents are shale-sandstones and conglomerates of gray, red, green and purple. None of the land-laid Triassic exposures is fossiliferous, though.

After cutting through the thick Middle Triassic terrestrial sequence for 1.5 miles, Cerro Gordo Road penetrates the marine Lower Triassic Union Wash Formation (roughly 235 million years old), some 1,800 feet thick. Unlike its classic fossil-rich outcrops in Union Wash northeast of Lone Pine, the exposures along Cerro Gordo Road bear only rare, fragmental ammonoids representing the genus Ussuria. The cephalopods occur in brownish-gray, silty limestones some 50 feet thick, along with abundant minute gastropod molds and infrequent pelecypodal lenses. The Union Wash Formation is wonderfully exposed for 0.8 mile, forming craggy reef-like ridges and colorful slopes composed of thin-bedded shales in hues of pale greenish-gray, light gray, yellowish-orange, and slightly greenish-yellow.

At a point 5.9 miles from State Route 136, Cerro Gordo Road intersects the Middle Pennsylvanian Keeler Canyon Formation (roughly 310 million years old). It's approximately 2,200 feet thick, a predominantly carbonate-shale sequence in which the arenaceous to argillaceous limestones often yield crinoid material and abundant tiny fusulinids that for the most part are only moderately well preserved. Typically, the shale interbeds are totally barren of paleontology--yet, from a perspective of casual inspection they seem so inviting, appearing eminently suitable for the preservation of many varieties of Paleozoic organisms. Persistent investigations of them may eventually reveal something truly remarkable.

For the next 1.1 miles, the Keeler Canyon Formation outcrops in prominent fashion along both sides of the road, affording easily accessible exposures for fossil explorations. Abundant small fusulinids and occasional disarticulated crinoid stems occur at irregular intervals throughout the carbonate sequence. At a point 7.0 miles from State Route 136, the Middle Pennslyvanian strata rest in a prominent fault contact against the older Upper Mississippian Chainman Shale (about 325 million years old).

The first Chainman outcrops encountered consist of smooth slopes underlain by dark gray to black carbonaceous shale and blocky-weathering argillite (a heat-and-pressure-altered clay shale), with subordinate interbeds of fine-grained sandstone and limestone. Periodic roadcuts during the next 1.3 miles--all the way up the remainder of the grade to Cerro Gordo Summit--reveal unfossiliferous brownish-red to dark gray argillites and characteristic thin-bedded, often cleavable black shales.

The fabulous Paleozoic Era fossils occur in grayish-black, slightly fissile shales of the Upper Mississippian Chainman Shale at a lone, isolated locality which lies in the vicinity of Cerro Gordo Summit; even though fossil specimens are quite common at the specific site, preserved through roughly 50 feet of well exposed strata, collectors will still have to watch carefully for the invariably small ammonoid casts and molds. On the other hand, common fragments of mature specimens demonstrate that the largest varieties here could grow to approximately 60 millimeters across (two and a half inches).

The most abundant ammonoid represented at the Chainman Shale site is Cravenoceratoides nitiloides, a type originally described from a locality near Yorkshire, England. Less commonly observed species of ammonoids include Cravenoceras nevadense, Cravenoceras richardsonianum, and Eumorphoceras bisulcatum.

A second variety of cephalopod occasionally encountered is Bactrites, referred to in scientific terms as an orthocone nautiloid cephalopod. Bactrites is in reality more closely related to the modern chambered nautilus than are the extinct ammonoids and ammonites, whose coiled morphologic aspect bear only a superficial resemblance. Paleontologists identify cephalopodic affinity not by the rough similarity of exterior shell designs but, rather, by the unique suture signature they happen to bear.

Based on their distinctive suture patterns, all ammonoids and ammonites can be classified into three separate orders: goniatitic (species with nonserrated sutures, generally considered the most primitive varieties)--the kind found in the Chainman Shale; ceratitic (sutures with serrated lobes); and ammonitic (very complex suturing--usually referred to as the most advanced order of ammonites--and the only order that can properly be termed an ammonite; the goniatitic and ceratitic types are necessarily called ammonoids). The goniatites first appear in the geologic record during the Devonian Period, some 370 million years ago; they persisted all the way up to the great dying at the conclusion of the Permian Period (when trilobites finally disappeared, as well), 252 million years ago. During the Permian Period both ammonoid and the ammonite varieties became common. But by Triassic times (252 to 201 million years ago), only the ceratitic forms proved particularly successful. Then they, too, died out at the conclusion of that geologic period, leaving only the ammonitic types, the ammonites proper, to carry on the cephalopodic heritage.

Throughout the Jurassic Period (201 to 145 million years ago) ammonitic ammonites thrived, becoming increasingly complex and numerous in the oceans of the Mesozoic world. They persisted right up to the close of the Cretaceous Period (66 million years ago), becoming extinct along with all the sensational terrestrial giants of that age--the dinosaur.

In addition to the cephalopods, the molluscan class Pelecypoda (or, Bivalvia--the bivalves--of more modern malacological terminology; an older designation was Lamellibranchia) is well represented in the Chainman exposures. The pelecypods here are typically much larger finds, easily spotted as reddish-brown limonitic impressions and silvery sheens--original lustrous shell material may be present some instances--on the darker grayish shales. Two of the more common varieties present include Caneyella wapanachensis and Caneyella richardsoni, each of which is frequently found preserved intact with both valves splayed open along the hingeline.

Not only are invertebrate fossils common in the Chainman outcrops, but fascinating fossil shark teeth can also be observed. For the most part, they occur as limonitic casts and molds, stained a pleasing reddish-brown on a grayish shale matrix, barely a few millimeters in length. One collector, though, has reported finding a three-quarters inch beauty with a distinctly serrated edge. Just what variety of shark they came from is anybody's guess, but it is quite exciting to come across an obvious tooth lying next to an ammonoid along the same bedding surface...a splendid fossil occurrence, indeed.

Of course, prior to September 2022, gathering and keeping any kind of vertebrate fossil on Public Lands was usually considered verboten, forbidden, but most folks used to understand that collecting shark teeth--the vertebrate equivalent of a common invertebrate fossil such as a brachiopod or coral, for example--specimens one is permitted to keep on BLM administered territory--was not in the same category as removing, say, dinosaur remains, or even mammalian skeletal elements from Public Lands, an activity that is universally not allowed since such specimens are considered "rare" and of vital importance to the scientific community.

Not any longer, though. New federal fossil collecting regulations became effective on September 1, 2022. According the US Department of The Interior, fossil shark teeth will no longer be considered a common fossil, comparable with common invertebrate and plant fossil material that folks can collect on BLM-administered lands (AKA, public lands) without a special permit. Beginning September 1, 2022, collecting fossil shark teeth on public lands (Bureau of Land Management/BLM) became illegal without a special permit issued solely to individuals with a minimum B.S. degree whose formal scientific research projects can be verified as authentic by the petitioned authorities.

Also present in the carbonaceous shales are common to abundant poorly preserved terrestrial plants, most of which were likely derived from a nearby coal-swamp paleoenvironment. The most readily recognizable forms resemble slender algal structures preserved as faint fragmentary outlines of vermiform configuration. The second group consists of branching stems and flat, straight impressions of rushes and ferns.

Lying directly above the fossiliferous grayish shales is an inconspicuous three-foot layer of silty limestone. Most often, a thick talus overburden of weathered shales masks its presence, but careful inspection of the narrow horizon usually discloses a wonderful variety of Paleozoic invertebrate remains--including the corals Triplophyllites and Chaetetes; a fenestellid bryozoan; a trilobite (Proetus missouriensis); a gastropod (Pleurotomaria brazeriana); and the following brachiopods: Spirifer (two species), Composita lewisensis, Productus (two species), Diaphragmus elegans, and Dictyoclostus sp.

Such brachiopods, bryozoans and corals all add dramatically to the sensational plethora and variety of fossil specimens that can be recovered from the Chainman Shale locality, situated in the transitional northernmost Mojave Desert-westernmost Great Basin Desert along the crest of eastern California's Inyo Mountains, in the vicinity of Cerro Gordo ghost town.

While today's fossil specimens lie at an altitude of roughly 9,000 feet, during Late Mississippian geologic times they would have been buried perhaps thousands of feet below sea level by detritus eroded away from already long-vanished mountains. Now, in the rarefied atmosphere of the high Inyo Mountains, fossil collectors become deep-sea divers of the Paleozoic Era, plunging far below the surface of the eons to explore layers of lithified muddy ooze, to search for ancient animal life that once took in oxygen from many fathoms below Earth's surface of the ocean some 325 million years ago.

On-Site Images

Click on the images for larger pictures

Click on the images for larger pictures. Left to right--The view is eastward from Cerro Gordo Summit in the Inyo Mountains, California, near the intersection of Cerro Gordo Road and Swansea-Cerro Gordo Road, 8.3 miles from State Route 136. Elevation is nearly 9,000 feet; the steep slopes at extreme right of picture are composed of the Middle to Upper Devonian Lost Burro Formation, which locally yields profuse stromatoporoids (an unusual variety of sponge), brachiopods, crinoids and gastropods. The distant mountains all lie within Death Valley National Park, established in December of 1994. Right--The drive up to Cerro Gordo Summit along Cerro Gordo Road affords spectacular vistas; reddish-brown strata in foreground consist of the Upper Mississippian Chainman Shale. The view is west across Owens Valley to the Sierra Nevada.

Click on the images for larger pictures. Left to right--The "Narrows" along Cerro Gordo Grade--here, Cerro Gordo Road slices through an unnamed Middle Triassic terrestrial formation conisting of volcanic tuffs and breccias; four-wheel-drive is mighty handy to help negotiate the steep ascent and variable quality of the dirt trail; seen here a 1959 Willys jeep--complete with winch, gas carrier, water carrier, tow bar, and even a rack. Right--A view roughly southeast along Cerro Gordo Road to a long-abandoned tramway that served the Cerro Gordo mining district during its boom years (probably late 1800s to early 1900s). Reddish brown, stratified rocks in middle ground belong to the Middle Pennsylvanian Keeler Canyon Formation, which yields abundant fusulinids and crinoidal debris; bluish-gray, cliff-forming strata near skyline, in distance, are composed of the Lower Mississippian Tin Mountain Limestone; rocks lower on the mountain side (underlying the more slope-forming, hilly terrain) belong to the Middle to Upper Devonian Lost Burro Formation.

Click on the images for larger pictures. Left to right--The view is roughly south to a portion of Cerro Gordo Ghost town. Dark bluish rocks in the distance, along skyline, belong to the Lower Mississippian Tin Mountain Limestone, which locally yield abundant corals, brachiopods, and large crinoid stems; whitish-pale gray strata along lower slopes consist of dolomites in the Middle to Upper Devonian Lost Burro Formation. Right--A seeker of Paleozoic paleomtology investigates the prime fossil locality in the Upper Mississippian Chainman Shale, as exposed in the vicinity of Cerro Gordo ghost town near the crest of the Inyo Mountains. Ammonoids, orthocone nautiloid cephalopods, pelecypods, shark teeth, and even fragments of terrestrial plants occur in a 50-foot section of dark gray to black, commonly fissile, slighly metamorphosed shale; bluish-gray rocks at upper left of picture, just below the blue sky, belong to the Lower Mississippian Tin Mountain Limestone. 

Images Of Fossils

Click on the images for larger pictures

Click on the images for larger pictures. Left to right--Here's a pelecypod specimen, genus Caneyella, from the Upper Mississippian Chainman Shale, collected in the vicinity of Cerro Gordo. Notice how both valves have been preserved, splayed open along the hinge-line on the slightly metamorphosed 325-million-year-old chunk of shale; combined, both valves together measure 28 millimeters in diameter. Right--Here is an orthocone nautiloid cephalopod, genus Bactrites from the Upper Mississippian Chainman Shale, collected in the vicinity of Cerro Gordo ghost town; actual size of specimen is roughly 18mm long. 

Click on the images for larger pictures. Left to right--Ammonoids called scientifically Cravenoceratoides nitiloides (12 millimeters in actual diameter) on a slab of slightly metamorphosed shale from the Upper Mississippian Chainman Shale, Inyo Mountains, California. Right--A pelecypod, with both valves preserved splayed open along the hingeline, from the Upper Mississippian Chainman in the vicinity of Cerro Gordo Ghost Town, Inyo Mountains, California. Caneyella sp., 27 millimeters long in actual dimension.

Click on the images for larger pictures. Left to right--A pelecypod from the Upper Mississippian Chainman Shale in the vicinity of Cerro Gordo ghost town, Inyo Moungains, California. The specimen is Caneyella sp., 25 millimeters in actual length. Right--A shark tooth, species unidentified, from the Upper Mississippian Chainman Shale in the vicinity of Cerro Gordo ghost town, Inyo County, California. The specimen is 8 millimeters long.

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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. Yields insects, leaves, seeds, conifer needles and twigs, flowering structures, pollens, petrified wood, diatoms, algal bodies, mammals, amphibians, reptiles, bird feathers, fish, gastropods, pelecypods (bivalves), and ostracods.
  • 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.
  • Cambrian And Ordovician Fossils At Extinction Canyon, Nevada: Visit a site in Nevada's Great Basin Desert that yields locally common whole and mostly complete early Cambrian trilobites, in addition to other extinct organisms such as graptolites (early hemichordate), salterella (small conical critter placed in the phylum Agmata), Lidaconus (diminutive tusk-shaped shell of unestablished zoological affinity), Girvanella (photosynthesizing cyanobacterial algae), and Caryocaris (a bivalved crustacean).
  • 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).
  • Ice Age Fossils At Santa Barbara, California--Journey to the famed So Cal coastal community of Santa Barbara (about a 100 miles north of Los Angeles) to explore one of the best marine Pleistocene invertebrate fossil-bearing areas on the west coast of the United States; that's where the middle Pleistocene Santa Barbara Formation yields nearly 400 species of pelecypod bivalve mollusks, gastropods, chitons, scaphopods, pteropods, brachiopods, bryozoans, corals, ostracods (minute bivalve crustaceans), worm tubes, and foraminifers.
  • 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.
  • Fossil Plants In The Neighborhood Of Reno, Nevada: Visit two famous fossil plant localities in the Great Basin Desert near Reno, Nevada--a place to find leaves, seeds, needles, foilage, and cones in the middle Miocene Pyramid and Chloropagus Formations, 15.6 and 14.8 to 13.3 million years old, respectively.
  • Dinosaur-Age Fossil Leaves At Del Puerto Creek, California: Journey to the western edge of California's Great Central Valley to explore a classic fossil leaf locality in an upper Cretaceous section of the upper Cretaceous to Paleocene Moreno Formation; the plants you find there lived during the day of the dinosaur.
  • 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.
  • Plant Fossils At The La Porte Hydraulic Gold Mine, California: Journey to a long-abandoned hydraulic gold mine in the neighborhood of La Porte, northern Sierra Nevada, California, to explore the upper Eocene La Porte Tuff, which yields some 43 species of Cenozoic plants, mainly a bounty of beautifully preserved leaves 34.2 million years old.
  • 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.
  • Fossil Plants At The Chalk Bluff Hydraulic Gold Mine, California: Take a field trip to the Chalk Bluff hydraulic gold mine, western foothills of California's Sierra Nevada, for leaves, seeds, flowering structures, and petrified wood from some 70 species of middle Eocene plants.
  • Field Trip To The Alexander Hills Fossil District, Mojave Desert, California: Visit a locality outside the southern sector of Death Valley National Park to explore a paleontological wonderland that produces: Precambrian stromatolites over a billion years old; early skeletonized eukaryotic cells of testate amoebae over three-quarters of billion years old; early Cambrian trilobites, archaeocyathids, annelid trails, arthropod tracks, and echinoderm material; Pliocene-Pleistocene vertebrate and invertebrate faunas; and late middle Miocene camel tracks, petrified palm wood, petrified dicotlyedon wood, and permineralized grasses.
  • Fossils In Millard County, Utah: Take virtual field trips to two world-famous fossil localities in Millard County, Utah--Wheeler Amphitheater in the trilobite-bearing middle Cambrian Wheeler Shale; and Fossil Mountain in the brachiopod-ostracod-gastropod-echinoderm-trilobite rich lower Ordovician Pogonip Group.
  • Fossil Plants, Insects And Frogs In The Vicinity Of Virginia City, Nevada: Journey to a western Nevada badlands district near Virginia City and the Comstock Lode to discover a bonanza of paleontology in the late middle Miocene Coal Valley Formation.
  • 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.
  • 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.
  • High Sierra Nevada Fossil Plants, Alpine County, California: Visit a remote fossil leaf and petrified wood locality in the Sierra Nevada, at an altitude over 8,600 feet, slightly above the local timberline, to find 7 million year-old specimens of cypress, Douglas-fir, White fir, evergreen live oak, and giant sequoia, among others.
  • 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.
  • Late Miocene Fossil Leaves At Verdi, Washoe County, Nevada: Explore a fascinating fossil leaf locality not far from Reno, Nevada; find 18 species of plants that prove that 5.8 million years ago this part of the western Great Basin Desert would have resembled, floristically, California's lush green Gold Country, from Placerville south to Jackson.
  • Fossils Along The Loneliest Road In America: Investigate the extraordinary fossil wealth along some 230 miles of The Loneliest Road In America--US Highway 50 from the vicinity of Eureka, Nevada, to Delta in Millard County, Utah. Includes on-site images and photographs of representative fossils (with detailed explanatory text captions) from every geologic rock deposit I have personally explored in the neighborhood of that stretch of Great Basin asphalt. The paleontologic material ranges in geologic age from the middle Eocene (about 48 million years ago) to middle Cambrian (approximately 505 million years old).
  • 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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