Trilobites In The Nopah Range, Inyo County, California

Find 518 million year-old trilobites on the Mojave Desert

Contents For Nopah Range Trilobites:

Introduction Text: The Field Trip Images: On-Site Images: Fossils

Links: My Music  Links: My Fossils Pages Links: USGS Papers Email Address

Introduction

Visit a paleontologically significant site on California's Mojave Desert, southeast of Death Valley National Park, where many trilobites occur in the Lower Cambrian Carrara Formation, some 518 million years old.

And now for the obligatory words of caution. Endemic to the Mojave Desert of California, including the Las Vegas, Nevada, region by the way, is Valley Fever. This is a potentially serious illness called, scientifically, Coccidioidomycosis, or "coccy" for short; it's caused by the inhalation of an infectious airborne fungus whose spores lie dormant in the uncultivated, harsh alkaline soils of the Mojave Desert. When an unsuspecting and susceptible individual breaths the spores into his or her lungs, the fungus springs to life, as it prefers the moist, dark recesses of the human lungs (cats, dogs, rodents and even snakes, among other vertebrates, are also susceptible to "coccy") to multiply and be happy. Most cases of active Valley Fever resemble a minor touch of the flu, though the majority of those exposed show absolutely no symptoms of any kind of illness; it is important to note, of course, that in rather rare instances Valley Fever can progress to a severe and serious infection, causing high fever, chills, unending fatigue, rapid weight loss, inflammation of the joints, meningitis, pneumonia and even death. Every fossil prospector who chooses to visit the Mojave Desert must be fully aware of the risks involved.

Field Trip To The Nopah Range

One of the more prolific producers of trilobites in the Mojave Desert-Great Basin region of eastern California is the lower to middle Cambrian Carrara Formation, a sedimentary rock deposit that has yielded more than 95 species of trilobites distributed among 38 genera. The Carrara was first described in the geological literature from excellent and characteristic exposures in Carrara Canyon, at Bare Mountain, a few miles south of Beatty, Nevada, where metamorphosed carbonates in the youngest periods of sedimentary deposition yielded vast quantities of high-grade, commercially exploitable marble, productive deposits that were extensively mined in the early portion of the 20th century. By a curious twist of fate, though, the Carrara Canyon outcrops of the Carrara yield few identifiable fossil remains. Trilobites are virtually nonexistent there, save for a few poorly preserved fragments of the exoskeleton, such as spines and free cheeks from the cephalon, or head shield. It is therefore a very disappointing region to explore, at least in a paleontological sense.

More productive exposures can be visited in the Funeral Range of eastern California--that impressive hulk that guards the eastern borders of Death Valley National Park. The problem here, obviously, is that unauthorized fossil collecting within the borders of the national park is not permitted. Yet, such classic sites as Echo Canyon, Titantothere Canyon and Pyramid Peak--all tucked away within the rugged and wild Funeral Range--continue to lure amateur fossil seekers, curious to observe in situ, with hands obediently kept off the rocks, the beautiful trilobites preserved along the bedding planes.

In western Nevada, most of the classic trilobite-bearing beds in the Carrara Formation occur on the Atomic Energy Commission Nuclear Test Site, which lies east of Highway 95 from the vicinity of Scotty's Junction all the way south to Las Vegas. Paleontologists privileged enough to gain access to the site report beautiful trilobite specimens, some of them complete, from a number of Carrara Formation exposures at Striped Hills, Jangle Ridge, and the Spectre Range.

In addition to Carrara Formation exposures lying within Death Valley and the nuclear test site, amateur fossil collectors face yet another obstacle. Much of the Mojave Desert is a now a federally protected wilderness area, or a national monument. For example, one of the more frequently visited outcrops of the Carrara used to be Eagle Mountain, south of Death Valley Junction (just east of the Death Valley National Park border), where abundant, identifiable trilobites had been collected for decades. The locality now lies within the federally designated Eagle Mountain Wilderness and it is completely off limits to any manner of unauthorized collecting.

Another broad band of productive trilobite-bearing Carrara Formation exposures can be visited in the Nopah Range, Inyo County, California. While it's true that most of the Nopah Range has been swallowed up by the bureaucratically established Nopah Wilderness, there is still one productive place where trilobites still occur on Public Lands--all from a single unit of slightly metamorphosed shale that is uppermost lower Cambrian in geologic age (or roughly 518 million years old). The locality lies in the Nopah Range and has attracted much attention of late from many amateur fossil enthusiasts, since this particular site represents one of the few accessible places remaining in all the southwest where unauthorized explorations of the Carrara Formation are allowed to take place.

As one gazes to the mountain slopes in the Nopah Range in the vicinity of the fossil site, the Carrara Formation is the essentially recessive interval, some 1,200 feet thick in ostensible stratigraphic thickness, though in actual fact it's considerably thicker than that in scientifically measured areas of outcrop, due to faulting and repetition of some of the sedimentary beds. The formation lies between two massive layers of widely differing lithologies--a dark bluish carbonate layer at the top called the middle to upper Cambrian Bonanza King Dolomite, and pale brown to dark brown quartzite below representing the lower Cambrian Zabriskie Quartzite. The Carrara is such a distinctive unit in the field, a varied mixture of tan, brown, and greenish shales interbedded with several massive beds of bluish to gray-blue limestone, that it can be followed with ease throughout the Nopah Range. But don't touch anything within the Nopah Wilderness (a detailed map delineating the geographic extent of the Nopah Wilderness can be obtained from the BLM). At the trilobite locality, the Carrara Formation can be observed lying below the massive bluish carbonate accumulations of the middle to upper Cambrian Bonanza King dolomite. The Bonanza King yields few trilobites, but is known to contain locally abundant oval algal structures called Girvanella signifying deposition in a warm, shallow Paleozoic Era sea.

Throughout its area of outcrop, the Carrara can be separated into nine easily distinguished stratigraphic subunits, or members. The youngest member, just below the overlying Bonanza King Dolomite, is the Desert Range Limestone. It can be recognized from afar due to its distinctive lithologic mixture of thin-bedded black silty limestone interbedded with orange dolomitic partings. The Desert Range is noted producer of Glossopleura trilobites, representing a middle Cambrian geologic age, but almost all of the productive beds lie on the nuclear test site in western Nevada.

Immediately below the Desert Range Limestone is the Jangle Limestone Member, which is the uppermost, or youngest, of the three major carbonate units in the Carrara Formation. It's characterized by one to as many as five massive limestone layers separated by thin argillaceous partings. In the Grapevine Mountains of eastern California, the Jangle yields a diverse and abundant middle Cambrian trilobite fauna consisting of Mexicella grandoculus, Mexicaspis radianis, Nyella climlimbata, Ptarmiganoides hexantha, and Volocephalina connexa. Exposures of the Jangle Limestone Member in the Nopah Range yield only sparse trilobite fragments and occasional algal nodules of the Girvanella variety. The algal structures are usually referred to by sedimentologists as oncolites, and were theoretically formed by direct precipitation of calcium carbonate from Cambrian sea-waters, unlike modern algal bodies from the Bahamas that develop directly through accretionary capturing of the surrounding oceanic muds.

In descending order of geologic age, the next oldest unit in the Carrara is the Pahrump Hills Shale Member. It consists of a heterogeneous accumulation of red-and-green mudstone, tan siltstone, silty limestone, and dolomite. Typically, the lowermost exposures produce abundant invertebrate tracks and trails preserved on the bedding planes of an orange-brown siltstone, while strata higher in the section often yield abundant oncolites embedded in a cryptalgal limestone. Even though the Pahrump Hills Shale reveals abundant trace fossils--including problematic trilobite feeding grooves, scratch marks, and profuse tracks clearly allied with arthropodal life movements--trilobite fossils are scarce to nonexistent at most outcrops. The most productive trilobite-bearing sites include the Grapevine Mountains in California and the Groom, Desert, Spectre and Belted ranges in western to central Nevada. Trilobites identified from those localities include Albertelloides rectinmarhinatus, Caborcella pseudaulax, Caborella reducta, Chancia venusta, Kootenia germona, Pachyaspis gallagari, Pagetia resseri, Sysacephalus obscurus, Volocephalina connexa, Zancanthoides sp., Albertellina aspinosa and Elrathina antiqua. All of the specimens suggest a middle Cambrian age for the Pahrump Hills Shale Member.

Underlying the Pahrump Hills Shale is the Red Pass Limestone Member, named for Red Pass, which lies roughly three-quarters of a mile east of Titantothere Canyon in Death Valley National Park. The Red Pass is easily distinguished in the Carrara section since it forms a prominent carbonate cliff face in a section dominated both above and below the interval by more recessive-weathering shales. Limestones in the Red Pass produce invertebrate tracks and trails, in addition to occasional oncolites, sometimes found in a superior state of preservation. Thin sections of the algal material yield actual filaments from the original plants, an extinct species of blue green algae. Other varieties of fossils remains are generally rare, occurring only in the uppermost and lowermost layers. These include such trilobites as Kochaspis augusta, Kochaspis lilian, Kochiellina groomensis, Kochielina janglensis, Plagiura extensa, Plagiura vetracta, Plagiura cercops and Schistometopus sp. Paleontologists agree that the Red Pass Limestone Member is entirely middle Cambrian in geologic age.

Lying directly below the Red Pass Limestone, in conformable fashion--that is, there were no apparent breaks in sedimentary deposition--is perhaps the most reliably fossiliferous unit in all the Carrara Formation--the fabulous Pyramid Shale Member, which was named for Pyramid Peak in the eastern sector of Death Valley National Park. Until 1994, when the California Desert Protection Act became law, Pyramid Peak could be found outside Death Valley National Monument. The prominent geographic landmark, and productive fossil locality, presently resides within the boundaries of Death Valley National Park: Fossil collecting there is obviously illegal without prior authorization from the Death Valley National Park Resources Division. If you think that you might possibly qualify for a collecting permit (a minimum B.S. degree from an accredited institution of higher learning is necessary, in addition to a valid research project that can be verified through independent investigation by the petitioned authorities), contact the DVNP Resources Division.

Not only is the Pyramid Shale Member fossiliferous at its type locality, but trilobites can be found at most of its exposures throughout the deserts of eastern California and western Nevada. It is in fact the most fossiliferous unit in the Nopah Range and is the member within which the trilobite locality discusssed here occurs in the Nopah Range--although, it should be noted that not all investigators agree with this assessment. Professor Matthew J. James of Sonoma State University, California, for example, believes that the fossils found in what's here called the Pyramid Shale Member actually occur in either the older Echo Shale and/or Eagle Mountaun Shale Member of the Carrara Formation; so do several dedicated trilobite hunters, as well. In either case, the fossils also show up near the main locality, within the Nopah Wilderness, but don't even think about keeping anything found there, because that area is presently under federal jurisdiction and administered by the Bureau of Land Management: it is therefore completely off-limits to unauthorized collectors. Be sure to have an up-to-date, accurate map of the Nopah Wilderness while exploring the Nopah Range for trilobite localities.

It should be noted that there is nothing in the original language of the Wilderness Act (circa 1964) that specifically allows hobbyists to excavate for minerals, fossils, or any other natural resources within a designated wilderness area. The final approval to collect on wilderness lands likely rests with the individual BLM ranger in charge of his or her district. Therefore, always check with the local district ranger before collecting within a wilderness region: some rangers, for example, may permit only surface collecting within their particular jurisdiction, such as what's allowed to take place within the Southern Inyo Wilderness at Union Wash near Lone Pine, California, where many freely eroded species of Early Triassic ammonoids can be gathered from surface exposures only--no digging into the bedrock is allowed there without a special use permit, which is issued only to professional paleontologists and geologists conducting formal, technical research projects. Wilderness areas administered by the U.S. Forest Service (in national forests, for example) are completely off-limits to any kind of unauthorized collecting--don't even bother to ask.

At the Nopah Range fossil trilobite locality, the specimens occur in greenish shales and maroon siltstones interbedded with a minor amount of barren quartzite and limestone in the lowermost 30 feet of the Pyramid exposures. Trilobites are relatively common at this site, appearing as fragmentary portions of the arthropod's original exoskeleton: Cephalons, thoracic segments, and infrequent pygidia constitute the primary finds. Extended periods of assiduous hunting--that is, several hours spent splitting shales along their natural bedding planes of deposition (the blunt end of a rock hammer works best, in combination with a selection of well-tempered chisels for the more massive chunks one might yank out of the outcrops)--may net a complete specimen or two, but don't count on it. There are no guarantees of perfect trilobite remains from an Early Cambrian locality. The fragile exoskeletons of the earliest trilobites in the fossil record tended to disassociate quite easily upon the death of the animal, or during the periodic molting process, when the arthropod discarded its outgrown cover for an external shield more suitable to its larger size. Do not became overly discouraged, though. Articulated, mostly complete trilobites do indeed occasionally show up here. Typical early Cambrian trilobites identified from the Pyramid Shale at the Nopah Range site include Olenellus clarki; Olenellus gilberti, and Nephrolenellus multinodus. Higher in the section, trilobites become exceedingly rare, although the following middle Cambrian forms have been recognized from the Groom and Belted ranges in western Nevada: Poliella lomataspis, Sysacephalus longus, Oryctocephalus nyensis, and Pagetia sp.

The Pyramid shale can be traced throughout the Nopah Range. While fossil-prospecting outside the boundaries of the Nopah Wilderness, simply watch for the greenish shales and maroon siltstones sandwiched between two massive layers of bluish limestone. Fossil prospectors here will likely observe numerous trenches in the Pyramid shales all along the Nopah Range, where it is permissible for amateurs to collect.

For the past number of years, a noted trilobite specialist has studied a key section of the Carrara Formation in the Nopah Range, a specific site that the paleontologist, in a guide book to the various Cambrian stratotypes in the Great Basin, proclaimed produced "not uncommon" perfect trilobite specimens. An examination of that locality, which lies at the top of the proposed Dyeran Stage of the lower Cambrian Waucoban Series (in strata older than the Pyramid Shale), proved conclusively to this writer, at least, that that specific stratigraphic section does indeed contain trilobites of potentially exceptional preservation (for early Cambrian trilobites, of course); even though the specimens there remained mostly fragmental, this writer did indeed observe a few semi-articulated carapaces of genus Peachella trilobites in already split shales lying atop huge spoils piles of discarded rock--not breathtakingly complete trilos, mind you, but there was enough paleontology present to suggest that if one could dedicate numerous man-hours to splitting shale there, one should definitely be able to recover several quality articulated trilobites, eventually. Indeed, that geologic section turned out to be a major tantalizing experience. Of course, this statement will only serve to further drive the curiosity of many a fossil seeker, who will strive to track down the locality to dertermine on his/her own whether trilobites preserved there are in a superior grade of perfect to near-perfect preservation. Be forewarned, though. The locality lies within the federally designated Southern Nopah Wilderness area. Look and touch, but don't dig there, and don't keep anything you find, except in a camera--unless you've secured a necessary collecing permit from the BLM (Bureau of Land Management), a permit issued only to folks with a minimum B.S. degree from an accredited university who seek to undertake scientific projects that can be fully verified by the petitioned authorities.

The fossiliferous Pyramid Shale Member lies in sharp stratigraphic contact directly above the underlying Gold Ace Limestone Member. The bulk of the Gold Ace is an oncolite-bearing microspar limestone, an extremely fine-grained carbonate unit that was originally deposited in a shallow oceanic setting as a lime mud. Some bedding planes yield abundant fragmental trilobites, mostly unidentifiable, though sections at Titantothere Canyon in Death Valley National Park have yielded Olenellus puertoblancoensis, Olenellus howelli and Olenellus sp., all of which demonstrate an early Cambrian age for the Gold Ace Limestone Member.

The next oldest unit in the Carrara Formation is the Echo Shale Member, named for its distinctive occurrence in Echo Canyon, Death Valley National Park. It's predominantly a green micaceous platy shale, uniformly unfossiliferous, except for one rare occurrence at Titantothere Canyon, where paleontologists identified a lone trilobite, Olenellus clarki. What's intriguing about this specific member in the Carrara, though, is that its lateral correlative shale unit is none other than the spectacular lower Cambrian Latham Shale, exposed in the Providence and Marble Mountains of San Bernardino County, California. The Latham Shale has probably produced more trilobite specimens than any other lower Cambrian formation in the western states. For example, the once prolific trilobite quarry in the Marble Mountains is justifiably world famous (though it's presently much-depleted in fossil specimens from decades of intensive collecting), and now lies within the federally estabished Mojave Trails National Monument, where the BLM (Bureau of Land Managment) continues to allow the recreational/hobby gathering of reasonable amounts of common invertebrate fossils--including there the prized arthropodal trilobites.

Next-oldest of the nine Carrara members is the Thimble Limestone Member, first described at Thimble Peak on the west side of Titantothere Canyon. The Thimble is chiefly an argillaceous dolomitic limestone that weathers to shades of orange, brown, and black. Some limestones in its northwesternmost exposures yield abundant fragments of echinoderms, hyolithids (a diminutive conical lophophorate that bears a distant relationship to brachiopods), and trilobites. At a few localities, abundant identifiable trilobites have been recovered, including Bristolia anteros, Bristolia brisolensis, Bristolia fragilis, Olenellus clarki, Olenellus euryparia, Olenellus fremonti, Olenellus howelli, Olenellus puertoblancoensis, Peachella brevispina, and Peachella iddingsi. It is also interesting to note that the trilobite-bearing portions of the Thimble Limestone Member probably correlate with at least part of the Latham Shale, as well. Unfortunately, the Thimble Limestone is not recognized in the Nopah Range, where the overlying Echo Shale and older Eagle Mountain Shale Members combine to form an undifferentiated sequence.

The oldest unit in the Carrara Formation, lying directly atop the lower Cambrian Zabriskie Quartzite (which yields vertical trace fossil worm borings paleontologists usually call Skolithus--generally considered a member of the Phylum Phoronida, or the Horseshoe Worms) in stunning fashion, is the aforementioned terrigeneous Eagle Mountain Shale Member. This is a slope-forming silty shale unit that weathers out in shades of green and gray-brown. It was named for its typical exposures at Eagle Mountain, a few miles north of Shoshone, where it reaches its greatest topographic development. Though generally unfossiliferous, the Eagle Mountain Shale has nevertheless produced two identifiable trilobites, Olenellus arcuatis and Olenellus cylindricus, from green micaceous shales in the lowermost few feet of the sections exposed at Echo Canyon and Titantothere Canyon.

The single best reference work dealing with the Carrara Formation is Physical Stratigraphy and Trilobite Biostratigraphy of the Carrara Formation (Lower and Middle Cambrian) in the Southern Great Basin, United States Geological Survey Professional Paper 1047, by Allison R. Palmer and Robert B. Halley, published in 1979 (at last check, still available from the USGS) In addition to naming and precisely detailing all nine members of the Carrara Formation, Palmer and Halley also describe and figure every one of the 95-some species of trilobites thus far identified; it is, indeed, a monumental contribution to paleontology and stratigraphy. As the authors note, the Carrara Formation is not richly fossiliferous, but it yields the most complete representation of early to middle Cambrian trilobites yet described from North America.

An added bonus for collectors is that this trilobite locality in the Nopah Range is easily accessible and a very productive. Amateurs are still welcome to visit it, as long as the area continues to remain free from litter, graffiti and vandalism. The BLM reserves the right to close the place down without advance warning, and they will most certainly do just that if visitors abuse their privileges here. With so many exceptional fossiliferous exposures of the Carrara Formation already closed due to Wilderness and California Desert Protections acts, it would be a shame to lose yet another, this time to our own boorish behavior.

On-Site Images

 

Click on the images for larger pictures. Left to right--Here is the primary trilobite-bearing locality in the Nopah Range, Inyo County, California. The fossils occur in the Lower Cambrian Pyramid Shale Member of the Carrara Formation.

Right--The primary trilobite locality in the Lower Cambrian Pyramid Shale Member of the Carrara Formation occurs in the Nopah Range, Inyo County, California. The view here is eastward from the trilobite-bearing shales. 

Click on the images for larger pictures. Left to right--This a Google Earth Street Car capture from December, 2008, in the Nopah Range, Inyo County, California, in the vicinity of the fossil localities discussed in the field trip. Perspective is slightly west of north to one of the great uninterrupted lower to middle Cambrian geologic sections in all the Mojave Desert region. Road level is the lower Cambrian Zabriskie Quartzite, overlain by the trilobite-bearing lower to middle Cambrian Carrara Formation--all capped on mountain at far right by the middle Cambrian Bonanza King Dolomite. Click on the picture to view a detailed description of each lower Cambrian rock unit exposed along the mountainside.

Right--Here is a view looking roughly eastward to the Nopah Range--a view that reveals the dramatic geologic contact between the younger, cliff-forming dark blue to gray Bonanza King Dolomite (marked by BK, in bold lettering), middle to upper Cambrian in age, and the more recessive-weathering, slope-forming brownish shales, quartizites and carbonate layers of the underlying, and older, lower to middle Cambrian Carrara Formation (marked by C, in bold lettering), a trilobite-bearing rock deposit that can be traced throughout the Mojave Desert region.

Click on the images for larger pictures. Left to right--A view to the Nopah Range, Mojave Desert, Inyo County, California. Those reddish brown hills to ground level are composed of the lower Cambrian Zabriskie Quartzite, which yields locally abundant arthropod tracks and trails, in addition to Skolithos vertical tubes, presumably a feeding and/or living chamber of an extinct phoronid animal (commonly called a horseshoe worm, though in actual fact they're not annelids at all, but rather reside in the phylum Phoronida and feed with a special apparatus called a lophophore--akin to brachiopods and bryozoans). Middle ground orange-tinged strata belong to the lower to middle Cambrian Carrara Formation, which produces common trilobites within several of its subunits (members). And the bluish to gray material to the skyline, with that prominent white marble stratum, is the middle to upper Cambrian Bonanza King Dolomite, within which Girvanella nodules produced by an extinct cyanobacterial photosynthetic organism occur locally.

Right--A world-famous fossil locality in the undifferentiated lower Cambrian Eagle Mountain Shale and Echo Shale Members of the Carrara Formation, Mojave Desert, California; here's where at least one trilobite specialist reported finding "not uncommon" perfect trilobites. Note the red backpack at lower right for scale. The locality lies within the federally protected Southern Inyo Wilderness area; unauthorized fossil collecting is strictly verboten there without a special use permit issued by the BLM (Bureau of Land Management), a permit provided only to individuals with a minimum B.S. degree from an accredited university who seek to undertake research projects that can be fully verified as authentic by the petitioned authorities.

Images Of Fossils

   

Click on the images for larger pictures. Here's a slab of slightly metamorphosed, heat and pressure-altered shale from the lower Cambrian Carrara Formation, collected in the Nopah Range, Inyo County, California; it bears several head shields, or cephalons, from a variety of trilobite called Olenellus clarki.

Right--A closer look at a portion of the fossiliferous slab of slightly metamorphosed shale seen at left, collected from the lower Cambrian Pyramid Shale Member of the Carrara Formation, Nopah Range, Inyo County, California. The cephalons belong to Olenellus clarki.

   

Click on the images for larger pictures. A head shield, also called a cephalon, from the trilobite Olenellus clarki, collected from the Lower Cambrian Pyramid Shale Member of the Carrara Formation, Nopah Range, Inyo County, California.

Right--This is a head shield, also called a cephalon, from a trilobite called Nephrolenellus multinodus, observed in the Lower Cambrian Pyramid Shale Member of the Carrara Formation at Pyramid Peak, Death Valley National Park, California.

 

Click on the images for larger pictures. Left and right--Two articulated trilobites from the lower Cambrian Pyramid Shale Member of the Carrara Formation, Nopah Range, Inyo County, California. Called scientifically Nephrolenellus multinodus. Photographs courtesy Mark Webster. I edited and processed the images through photoshop. Middle--A mostly complete Olenellus clarki trilobite from the lower Cambrian Pyramid Shale Member of the Carrara Formation, Nopah Range, California. Photograph courtesy First Church of Trilobites. I edited and processed the image through photoshop.

 

Click on the images for larger pictures. Left and right--Articulated trilobites from the undifferentiated Echo Shale and Eagle Mountains Shale section of the Carrara Formation, Nopah Range, Inyo County, California. Called scientifically Peachella brevispina. Middle--An articulated Peachella iddingsi trilobite from the undifferentiated Echo Shale and Eagle Mountain Shale section of the Carrara Formation, Nopah Range, California. All photographs courtesy Mark Webster. I edited and processed the images through photoshop.

My Other Web Sites

My Music Pages

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.
  • 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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