Fossil Leaves And Seeds In West-Central Nevada

A classic Great Basin Desert middle Miocene paleobotanical locality

Contents for: Fossil Leaves And Seeds In West-Central Nevada

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The Field Trip

Perhaps the richest producer of Miocene-age (23-to-5.3-million-year-old) plants in the entire state of Nevada is a geologic rock deposit known as the Middlegate Formation. Its primary and most paleontologically productive exposures lie within a rather localized geographic area of west-central Nevada, where paleobotanists have identified some 64 species of fossil plants--including such diverse types as evergreen live oak, giant sequoia/Big Tree, willow, fir, maple, and spruce. The fossil specimens, which consist of leaves, winged seeds (called samaras in technical botanical terminology), acorn cups, seed pods and branchlets, occur as pale to dark brown carbonized impressions on a cream-white to pale-brownish matrix of opaline shale--many of them exhibiting such an exceptional degree of preservation that the original delicate venation on the leaves is clearly visible.

All of the remains are middle Miocene in geologic age, dated by radiometric methods at some 16 million years old. They occur in the uppermost (the youngest layers of deposition) 30 feet of the Middlegate Formation, just below the overlying Middle Miocene Monarch Mill Formation, whose basal sedimentary conglomerates have yielded to paleontologists a large vertebrate fauna, including the silicified bones of moles, rabbits, squirrels, beavers, mountain beavers, mice, weasels, martins, rhinocetotids, oreodonts, camels, llamas, and pronghorns.

Such scientifically invaluable fossil vertebrate material on Public Lands is of course off limits to all collectors who do not possess a special use permit issued by the Bureau of Land Management, a permit issued solely to individuals with a minimum B.S. degree from an accredited university whose research projects can be verified as authentic by the petitioned authorities--a formal collecting status that is likely well understood (and appreciated) by most amateurs and professional paleontologists alike. At present, though, there is no such legal restriction on the hobby gathering of leaves, winged seeds, petrified wood, and other paleobotanical remains from the Middlegate Formation--but that much-welcomed legally lenient status could of course change without advance warming.

The troubling circumstance is that, recently, commercial collecting interests have begun to concentrate on a select number of fossil leaf-yielding fields in Nevada--obviously those sites which happen to provide them with the greatest numbers of well-preserved specimens. Needless to report, this is patent illegal activity, since no fossil remains collected on Public Lands may be either sold or bartered (legal argot for the act of trading specimens). And while there is certainly nothing criminal about selling fossil specimens collected on private lands (with the land owner's unambiguous permission, of course), any desecration of a fossil horizon on Public Lands in an attempt to secure as many saleable remains as possible is without question an offense punishable by law. Also, such behavior is with sure consequence horribly counterproductive, since it only invites federal officials with the Bureau of Land Management and the Forest Service to close down popular fossil areas, preventing conscientious amateurs from sampling places of significant paleontological interest.

The Middlegate Formation locality certainly fits that description. It's a remarkably productive fossil plant-yielding region situated in the middle of the Great Basin Desert, amid what botanists call a shadscale desert flora, or an association of low, rigid, spinescent shrubs no more than two feet high. But 16 million years ago the Middlegate Formation district was the site of a deep, cool, clear-water lake, a great body of water into which creeks and streams occasionally discharged loads of fine detritus, along with abundant plant debris from the surrounding countryside--a landscape rich with conifers, deciduous varieties and evergreen live oaks which now lie preserved along the bedding planes of fine-grained shales.

The most efficient way to locate fossil plants in the Middlegate Formation is to dig into the slabby-weathering siliceous shales, exposing fresh sedimentary strata below the surface. Fortunately, most of the shales within a few inches of the surface are severely fractured; hence, little splitting of them is necessary, since they tend to separate from the outcrops in thin sheet-like plates. Watch closely for the fossil plant compressions and impressions along the bedding planes of every shale fragment you remove from the hillside exposures. The deeper you dig, though, the more thickly bedded the opaline shales become, until at last it will become necessary to begin splitting the extremely dense, concrete-like rocks. When doing this, always remember to wear safety goggles, or at least some kind of eye protection such as sunglasses. The denser, thick-bedded opaline strata crack apart only with the greatest of applied brute force, thus increasing the likelihood that sharp fragments might launch off the matrix into your eyes. Stand slabs of shale on end, then give them a sure whack with the blunt end of a geology hammer. If you're fortunate, the sedimentary layers will break apart along their original planes of deposition, revealing perfect carbonized leaf and seed impressions and compressions to their first light of day in approximately 16 million years.

By far, the most common specimens found in the Middlegate Formation are leaves and acorn cups belonging to an evergreen live oak, Quercus pollardiana, which is identical to the modern canyon live oak native to the western flanks of the Sierra Nevada and the coastal ranges of central California.

The 18 next most frequently encountered remains in the Middlegate shales include: interior live oak (leaves); Birchleaf mountain-mahogany (leaves); tanbark oak (leaves); common cattail (leaves); Bigleaf maple (leaves and samaras); Balsam poplar (leaves); willow (leaves); Boxelder (samaras and leaflets); Brewer spruce (samaras); Tigertail spruce (samaras); silver maple (samaras and leaves); Arizona madrone (leaves); Catalina ironwood (leaves); Giant Sequoia (branchlets); New Mexican locust (leaflets and seed pods); California Red fir (samaras and needles); small-stemmed Horsetail (stems); and Ponderosa Pine (samaras and needles).

Twenty of the rarest species reported from the Middlegate Formation include: Golden Chinkapin (a brush-sized variety--leaves); Paper birch (leaves); Hairy mountain-mahogany (leaves); quaking aspen (leaves); Utah juniper (branchlets); an extinct water oak (leaves); Narrowleaf cottonwood (leaves); a second species of willow (leaves); White ash (samaras); Oregon grape (leaves); Alaskan cedar (branchlets); water lily (leaves and rootstocks); Rocky Mountain hawthorn (leaves); Rocky Mountain maple (samaras and leaves); Douglas-fir (samaras); Mountain hemlock (samaras); Golden chinkapin (tree variety--leaves); East Asian maple (samaras and leaves); and Cedrella (samaras).

The Middlegate fossil flora was discovered in the Spring of 1949 by Laura Mills, an avid amateur fossil collector from Fallon who at the time was searching for petrified wood. She brought the rich fossil deposit to the attention of paleobotanist Daniel I. Axelrod, who accompanied her to the locality in the early summer of 1949. Several weeks later Axelrod made his first substantial collection of plants from the Middlegate Formation--a fantastic array of Miocene species preserved in superior detail; here was certainly one of the most productive and important fossil plant localities in all the Great Basin.

Two years later, during the Spring of 1951, Axelrod made yet another visit to Middlegate, this time accompanied by his long-time field assistant Robert E. Smith, who maintained accurate records of the various plant taxa recovered from the shales. They spent an entire week in the field, eventually amassing a truly exhaustive selection of Miocene fossil plant material. In all, Axelrod and Smith gathered some 3,458 specimens from the Middlegate Formation, 2,917 of which belonged to the evergreen live oak Quercus hannibalii.

Axelrod published his scientific examination of the Middlegate plant material in 1956 in a formal scientific paper. In it, he described 42 specimens of ancient plants, assigning them a transitional Miocene-Pliocene geologic age, or what was then understood to be roughly 12 to 10 million years old.

Axelrod later revised the Middlegate fossil plant association in another formal paleobotanical publication. He based this new scientific analysis on supplemental collections of fossil plants supplied by Axelrod's students in paleobotany at the University of California, Davis, during the 1970s. The student collecting expeditions not only increased the total number of specimens known from the Middlegate Formation to 6,882, but also added some 22 new species of fossil plants to the ever-expanding paleobotanical record.

In addition to the larger plant collections, Axelrod also had at his disposal increasingly sophisticated and accurate radiometric methods of dating volcanic rocks interbedded in a sedimentary sequence. In the late 1960s, geologist Harold Bonham of the Nevada Bureau of Mines And Geology selected fresh samples from hornblende rhyolite tuffs present near the middle of the Middlegate Formation. When Bonham ran the volcanics through a series of radiometric-age analyses, paleobotanists were shocked to learn that the fossil plants could not be transitional Miocene-Pliocene as originally determined (12 to 10 million years old, prior to the recalibration of both the Miocene and Pliocene Epochs; for example, the Pliocene now begins at about 5.3 million years ago), but rather more in the range of 18.5 million years old, or middle Miocene in geologic age. More recent radiometric determinations, though, prove that the Middlegate Formation is younger still--more in the range of 16 million years ancient.

In his monographs dealing with fossil plants from Nevada, paleobotanist Daniel I. Axelrod concluded that the Middlegate Flora most closely resembles a modern sclerophyll forest, which reaches its ultimate development in the western Sierra Nevada and the coastal ranges of central California. Such a forest is dominated by evergreen dicotyledons, principally madrone, Golden chinkapin, tanbark oak and several specimens of oak; typical evergreen shrubs include buckbrush, mountain mahogany, toyon, sumac, and manzanita--all of which contribute to a classical chaparral botanic association. In addition to the evergreen species, a typical sclerophyll forest can also include such deciduous types as maple, ash, black walnut, sycamore, cottonwood, currant, rose and willow, each of which prefers the moister sites around streams and seepages.

The association of sclerophyllous species found in the Middlegate Formation suggested to Axelrod that the fossil plants lived under environmental conditions quite similar to those present today in the Santa Cruz and Santa Lucia Mountains along the coast of central California. There are also obvious relationships to the modern groves of Giant Sequoia in both the northern and southern portions of the Sierra Nevada, particularly the North Grove (southeast of Auburn) in Placer County and the Tule River Grove near Belknap Creek in Tulare County.

Based on the available geological evidence, the fossil plants accumulated in waters of moderate depth roughly one-half mile from the southern margin of the Miocene Lake, into which creeks and streams discharged detritus from south-facing slopes of volcanic origin during periods of intermittent storm runoff. Surrounding the basin of deposition and reaching down to lake level was a dominantly sclerophyllous forest consisting of madrone, Golden chinkapin, tanbark oak, canyon live oak, interior live oak, and water oak. Drier sites in the ancestral Middlegate Basin supported such shrubs as buckbrush, mountain-mahogany, toyon, Lyontree, and locust. The stream banks were lined with species of maple, cottonwood and willow, while higher elevations along the distant slopes supported an impoverished conifer-hardwood forest of fir, spruce, pine, Alaska-cedar, Douglas-fir, and Giant Sequoia. Associated with the conifers were such deciduous varieties as alder, maple, hawthorn, willow, and mountain ash.

Summer rain indicators in the Middlegate Flora include types whose closest modern relatives live in the eastern United States, eastern Asia, and the southern Rocky Mountains--such deciduous species as birch, persimmon, hawthorn, hydrangea, Oregon grape, maple, and cottonwood. All of these varieties prove that throughout Middle Miocene times there must have been, at a minimum, some two to three inches of precipitation during each of the three summer months; this contrasts wildly with the extreme aridity of the Middlegate Formation territory today, which receives on average only 5 inches of rain per year.

Yet, 16 million years ago the Middlegate Basin received approximately 35 to 40 inches of rain on an annual basis, an estimate based on the known environmental requirements of living members of the fossil flora. The middle Miocene Middlegate climate can be categorized as mild-temperate, with an average temperature reading for the month of January of 40 degrees; today temperatures there remain below freezing throughout January, averaging a chilly 30 degrees. Summertime weather conditions were also more moderate during middle Miocene times, when typically an entire month of July averaged fully 10 degrees lower than that experienced in the area today--68 degrees for the Miocene, compared with 78 in the present-day. Elevations at the site of deposition were likely much higher than today's 5,000 to 5,300 feet--more in the neighborhood of 8,000 feet. This estimate is based on rather recent sophisticated geophysical and paleobotanical studies which demonstrate that 16 million years ago the ancestral Great Basin region stood appreciably higher than it does at present; by 6.8 million years ago, elevations had collapsed through extensional geologic stresses to roughly the same as what we see today in the Great Basin.

Here is certainly one of the premiere fossil localities in all of Nevada: the Middlegate Formation, a place where professional paleobotanists and amateur fossil enthusiasts alike have recovered through a period of several decades thousands upon thousands of well-preserved leaves, seeds, acorn cups, seed pods, conifer needles, and branchlets. Today, the site lies within the brutal aridity of a shadscale desert, a land of low spiny shrubs adapted to harsh alkaline soils, great extremes in temperatures, and scant rainfall--as low as 5 inches per year. It's a scene radically different from the one which existed throughout this portion of the Great Basin some 16 million years ago, when vegetation identical to that now living near the Giant Sequoia groves in the western Sierra Nevada and in the coastal ranges of central California thrived in a moist land of ample rainfall--where a great pristine lake splashed the trunks of canyon live oak and Giant Sequoia.

On-Site Images

Click on the images for larger pictures. Here are two views of the famous Middlegate Formation fossil flora locality. At left is a photograph taken from a distance of about two miles from the Middlegate Formation, which is composed of lacustrine (lake-deposited) cream-white to pale-brownish opaline shales, within which a genuine bonanza of beautifully preserved fossil leaves, seeds, and branchlets can be found. At right is an image of the prime fossil plant-bearing site in the midst of the Middlegate Formation; here, the rounded hills composed of siliceous opaline shales produce some 64 species of ancient plants from the middle Miocene epoch, roughly 16 million years old.

Click on the images for larger pictures. Left to right--Parked in the wash which leads to the middle Miocene Middlegate Formation fossil locality, proper. Preparing to park along right edge of wash. Low hills at right distance must be hiked over to locate best exposures of the cream to whitish fossiliferous opaline shales, a representative outcrop of which can be seen just to the right of jeep. Right--An explorer of middle Miocene times "assumes the paleobotanical position"--nose to the ground, seeking with deliberate diligence the wonderfully preserved fossil leaves, seeds, acorn cups, and branchletts in the middle Miocene Middlegate Formation, some 16 million years ancient.

Evergreen Live Oak Leaves

Click on the images for larger pictures. Here are two 16-million-year-old fossil evergreen live oak leaves from the middle Miocene Middlegate Formation, a classic fossil leaf and seed locality situated in the Great Basin Deser; both specimens are complete leaves from Quercus pollardiana, a species of evergreen live oak that is identical to the living canyon live oak now native to the western foothills of the Sierra Nevada and the coastal mountain ranges of central California. The specimen at left is 45 millimeters long; leaf at right is 35mm in length. The Middlegate Formation fossil flora yields some 64 species of ancient Middle Miocene plants roughly 16 million years old.

Oak Leaves

Click on the images for larger pictures. Fossil leaves from the middle Miocene Middlegate Formation, Nevada. At left is a complete leaf specimen from the extinct water oak, Quercus simulata, 50 millimeters in length; at right is an essentially complete leaf (stem is partially obscured by opaline shale matrix) from a tanbark oak, Lithocarpus nevadensis, which is 65mm long.

Spruce-California Red Fir Seeds

Click on the images for larger pictures. Here are two fossil conifer winged seed (samaras in botanical terminology) from the middle Miocene Middlegate Formation, Nevada: Specimen at left is a seed from the Miocene species of Brewer spruce (now native to the Klamath Mountains of northwestern California), Picea sonomensis, 15mm long; at right is a seed from the Miocene variety of California Red fir, Abies laticarpus, which is 30mm in length.

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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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