Fossil Plants At Aldrich Hill, Nevada

Visit a remote fossil locality near Yerington, Nevada, where some 35 species of ancient plant remains can be collected from the middle Miocene Aldrich Station Formation, approximately 13 to 12.5 million years old--including the leaves of evergreen live oak, winged seeds from spruce, and giant sequoia foliage.

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Field Trip To Aldrich Hill, Nevada

The Great Basin wilds of west-central Nevada are rich in productive fossil plant localities. While they are probably not as well known to amateur fossil plant hunters as the classic Paleocene through late Miocene (roughly 64 to 5.3 million years ago) leaf-bearing sites of Oregon, Idaho, Washington, Montana, Colorado and Wyoming, the Nevada fossil plant deposits continue to yield many excellently preserved paleobotanical remains.

One of the more interesting and paleontologically rewarding leaf and seed-yielding areas lies near Yerington (the county seat of Lyon County) at Aldrich Hill. Here can be collected some 35 species of ancient plants from what geologists call the middle Miocene Aldrich Station Formation, a geologic rock unit dated at roughly 13 to 12.5 million years old. Among the many fossil plant remains found at Aldrich Hill are complete, carbonized leaves from an evergreen live oak, in addition to many conifer winged seeds and even giant sequoia foliage. It is indeed a special place to visit, an isolated region in the Great Basin "outback" where the Bureau of Land Management still permits the hobby collecting of fossil plant remains--a situation that could change literally overnight, by the way, should commercial collecting interests begin to raid the stratigraphic section, desecrating the integrity of the exposures and destroying in the process the great scientific value of the locality. Fortunately, Aldrich Hill remains accessible to the general public, and folks interested in collecting fossil plants there for personal use only may continue to visit, remembering of course that such specimens gathered must be neither sold nor bartered--activities which would constitute a clear violation of the rules and regulations established by the Bureau of Land Management for visitors to America's public lands.

All of the fossil plants--including evergreen live oak leaves, spruce winged seeds, conifer needles, alder cones, and giant sequoia/big tree foliage--occur in the tan to reddish-brown and cream-colored diatomaceous to tuffaceous mudstones and shales of the middle Miocene Aldrich Station Formation exposed on the north side of Aldrich Hill. Excellent outcrops of the plant-bearing strata can be examined along the main wash which trends generally east-west across the northern side of Aldrich Hill. Additional productive fossiliferous exposures can also be found in the minor erosion gullies that dissect the north slope of the hill. It should also be pointed out that virtually every outcrop of diatomaceous mudstones and shales in the Aldrich Hill district yields fossil plant material in varying degrees of relative abundance, from very rare to common, although the prominent and accessible exposures along the north side of the hill have in a historical sense provided collectors with the majority of paleobotanical remains.

When fossil hunting at Aldrich Hill, as at most other fossil leaf and seed-yielding localities, try to cover as much terrain as possible in search of the most productive layers. Split heaps of the shales with the blunt end of a geology hammer whenever you stop for a "look-see." Some folks prefer to use the pick end, obviously, of a geology rock hammer, though this technique actually decreases the likelihood of splitting with precision the blocky diatomaceous mudstones and shales; too, a number of collectors prefer a roofer's or brick-layer's-style hammer, with a wide narrow blade, which theoretically splits shales with great effectiveness. Such a hammer probably works well with very soft, classically fissile shales, but the tool lacks any kind of "punch," or heft, for cleaving bulkier, more compacted mudstones and shales. The upshot: the blunt end of a traditional geology hammer splits the Aldrich Station Formation diatomaceous shales and mudstones quite nicely. Remember, of course, to wear safety goggles, or some manner of eye protection while splitting the mudstones and shales.

Although nowhere abundant, the fossil plant impressions in the Aldrich Station Formation are nevertheless common and even obvious at several horizons in the diatomaceous material. Watch for their pale to dark-brown, carbonized coloration on the tan to reddish-brown and cream-colored rocks. Associated with the leaves, winged seeds, and twigs are conspicuous oval specimens roughly one-half to one inch in diameter. These fossils represent the internal molds of fresh water clam shells; the actual shell substance has long since been dissolved away, as the siliceous mudstones and shales were evidently a poor medium of preservation for the tests of pelecypods.

If a microscope is available, you can, in addition to finding the plants and clams, examine the remains of an especially prolific fossil type at Aldrich Hill--the diatom. This is a microscopic photosynthesizing single-celled alagae which during the geologic past, particularly in west-central Nevada in rocks of middle through late Miocene age (roughly 17 to 5 million years ago), contributed its resistant siliceous remains in vast numbers to the plethora of paleohistory in the rocks. The scientific extraction of diatoms for paleobotanical study is a dangerous operation, involving as it does the use of several powerful acids, among them hydrochloric, sulfuric and hydrofluoric--potent brews that if not handled properly can cause frightful, life-threatening burns. It is a process only an expert should attempt. Fortunately, though, you can get an adequate, general view of diatoms simply by powdering a small amount of diatomaceous matrix on a glass microscope slide and then examining the residues under moderate to high powers of magnification. Most of the diatoms from the Aldrich Hill district resemble minute boxcars and discs.

Excluding the numerous species of diatoms identified from the Aldrich Station Formation, some 35 species of fossil plants have been described from the exposures at Aldrich Hill--a fossil deposit first investigated scientifically in the early 1940s by the late paleobotanist Daniel I. Axelrod during one of his geological reconnaissance investigations in Nevada. Axelrod eventually published his paleobotanical, paleoecological, and geological conclusions concerning the Adrich Hill paleoflora in a monumental paleobotanical monograph, where he additionally describes in detailed scientific fashion three more important Nevada fossil floras (Middlegate Formation, Chloropagus Formation, and Desert Peak Formation). All of the fossils from Aldrich Hill occur in the Aldrich Station Formation, as named by Axelrod in his treatise, a geologic rock unit originally considered transitional Miocene-Pliocene (about 10 million years old by the geologic time scale then in fashion--as recalibrated, the Miocene-Pliocene is now established at roughly 5.3 million years ago), but now considered middle Miocene in geologic, or approximately 13 to 12.5 million years old.

The Aldrich Station paleoflora shows quite a variety in its composition. The five most commonly collected specimens are, in decreasing order of relative abundance: (1) winged seeds from three varieties of spruce--Picea sonomensis (by far the most abundant representative of the paleoflora), whose seeds appear identical to the modern Brewer Spruce (Picea breweriana) of the Klamath region of northwestern California and adjacent Oregon; an extinct spruce that Axelrod called Picea lahontense--a conifer whose seeds cannot be compared with any known living spruce, although they do show a general similarity to those produced by a few modern "larger-coned" spruces of eastern Asia, chiefly China; and a presumed extinct spruce called Picea magna, whose winged seeds resemble those produced by the living tiger-tail spruce, Picea polita, a conifer now native to the volcanic soils of Japan; (2) fragmental and occasional complete, intact leaves from an evergreen live oak called Quercus pollardiana, a species that is practically identical to the modern maul oak, also called canyon live oak, Quercus chrysolepis, presently native to the moist western slopes of the Sierra Nevada and the Coastal Ranges of California; (3) leaves from a species of cottonwood, Populus payettensis, whose fossil foliage matches leaves produced by the living Narrowleaf Cottonwood, Populus augustifolia; (4) foliage/twigs of giant sequoia, Sequoidendron chaneyi, that match very well with those produced by the living Sierra Redwood/Big Tree, Sequoiadendron giganteum, which is now restricted solely in natural habitat to a narrow, moist belt along the western slopes of the Sierra Nevada in California; and (5) leaves from a species of willow referred to as Salix payettensis--its foliage appears very similar, if not identical to leaves produced by the modern willow Salix exigua, a rather widespread variety that goes by many common names, such as Coyote Willow, sandbar willow, or even Narrowleaf willow. The nine next most-common specimens encountered are: Catalina ironwood, Mountain alder, an extinct water oak, California buckeye, black cottonwood, an extinct cottonwood, zelkova, Arizona ash, and Cedar elm. Rarer occurrences include such varieties as sugar pine, white fir, Ponderosa pine, Douglas-fir, Western Red Cedar, Western hemlock, California sycamore, serviceberry, Oregon grape, California coffeeberry, coralberry, japanese pagodatree, birch-leaf mountain mahogany, and a Horsetail.

The vast majority of fossil plants recovered from the middle Miocene Aldrich Station Formation at Aldrich Hill show a demonstrable resemblance to their modern analogs still living today. For example, the humid cooler-weather conifer elements in the paleoflora (spruce, fir, pine, giant sequoia) have their closest contemporary counterparts in the Sierra Nevada and Cascade Mountains regions of western North America. As a matter of fact, there is a direct relationship postulated between the overall composition of the Aldrich Hill Miocene flora and modernday plant associations present in the giant sequoia forests of the western slopes of the Sierra Nevada in California--specifically, the spectacular Sierra Redwood groves at Calaveras Big Trees State Park and Sequoia National Park.

Based on the known climatic requirements of present day plant counterparts of the fossil flora, the Aldrich Hill district some 13 to 12.5 million years ago had quite a different environment than the arid juniper-sage-Pinyon pine associations observed there today. For one thing, rainfall was approximately 25 to 30 inches per year, distributed in both winter and summer months. This is fully 15 inches more than the area receives today, with almost all of the effective precipitation now occurring during wintertime as snow and rain. Temperatures today also show much greater extremes than what can be inferred for the moderate middle Miocene days, when freezing conditions were extremely rare and summer highs normally ranged around 85 degrees. This contrasts dramatically with today's regular winter weather patterns that mimic Arctic-style extremes and summer peaks to over 100 degrees Fahrenheit. Elevations at the sites of deposition were in all likelihood slightly higher than the 6,000 to 6,700 feet we observe today in the Aldrich Hill district--probably an elevation between 7,000 and 7,500 feet for those middle Miocene times is not out of the question.

In addition to telling us something of the climate of the geologic past, the Aldrich Hill fossil plant bonanza also reveals a striking gradual change in both the local paleogeography and the associated plant communities. In the earliest phases of their deposition, the fossil plants reveal that the ancestral Aldrich Hill region was a broad valley within which sprawled one or more fresh water lakes of perhaps moderate to large size; the diatoms preserved in the Aldrich Station Formation suggest that the lakes were rather cool and deep and well within the range of normal mineral content. Occasionally, though, volcanic activity from distant areas contributed layers of ash and pumice to the accumulating diatomaceous sediments. The adjacent slopes supported a thick mixed conifer forest consisting of white fir, Ponderosa pine, Brewer spruce, Douglas-fir, Western Red Cedar, Western hemlock and giant sequoia, along with a subordinate deciduous grouping of alder, poplar, cottonwood, willow, elm, zelkova, japanese pagodatree, and coralberry. Living on the more exposed slopes were evergreen live oak, serviceberry, California buckeye, cottonwood and ash. Yet, higher in the geologic section at Aldrich Hill, in rocks younger by hundreds of thousands of years, the fossil plants prove that the geography had changed significantly. In place of a widespread conifer forest with only minor areas of woodlands surrounding a great lake basin, there had developed a vast hilly woodland where only a few interfingers of forest penetrated from the higher slopes surrounding the lake basin of deposition. Replacing big tree, spruce, pine and other conifers as dominants were evergreen live oak, mock locust, California buckeye, coralberry, mountain mahogany and serviceberry--a paleoenvironment that was much more xeric in nature than that suggested by plant communities which had preceded it. Here rare forest elements were white fir, Ponderosa pine, western hemlock and giant sequoia. Also present in the forest association were such species as alder, hollygrape, Catalina ironwood, cottonwood, poplar, elm, willow and zelkova. The once thriving forest grouping of conifers and deciduous varieties appears to have survived in the upland regions, descending into the dominant evergreen live oak territory only under especially favorable conditions.

Today, the sedimentary rocks at Aldrich Hill provide proof that roughly 13 to 12.5 million years ago an extensive giant sequoia forest reigned over what is presently an arid Great Basin land of sage and juniper and Pinyon pine. Along with the big trees grew such plant varieties as Brewer spruce, Ponderosa pine, white fir, Western hemlock, evergreen live oak, and an array of deciduous kinds--a scene that closely resembles the modernday humid western slopes of California's Sierra Nevada in the vicinity of Calaveras Big Trees State Park east of Angels Camp, where two groves of mighty Sierra Redwood continue to thrive in a setting of pristine grandeur. Within the diatomaceous mudstones and shales of the middle Miocene Aldrich Station Formation can be found direct evidence of that ancient Big Tree forest, the beautifully preserved carbonized impressions of plant remains covered over by the sediments in a long-vanished lake--leaves and seeds and conifer foliage which only await a patient, dedicated fossil hunter to bring to their first light of day in many millions of years.

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On-Site Images

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Click on the imagae for a larger picture. Left--Here is the view near Aldrich Hill, Nevada, looking essentially due north across the fossiliferous diatomaceous mudstones and shales of the 13 to 12.5-million-year-old middle Miocene Aldrich Station Formation (foreground and the hill at upper right), which yields 35 species of ancient plants.

Right--Looking northeastward from the western side of Aldrich Hill. Exposures of whitish sedimentary rocks in the foreground and in the distance belong to the fossil plant-bearing middle Miocene Aldrich Station Formation.




Click on the images for a larger pictures. Left--Collectors inspect a narrow erosion gully along the north side of Aldrich Hill, Nevada, for fossil plant remains in the middle Miocene Aldrich Station Formation; the view is roughly due west.

Middle--A collector gets down to business at an outcrop of the middle Miocene Aldrich Station Formation along the north side of Aldrich Hill, Nevada. The regularly bedded, tan to reddish brown and cream-colored diatomaceous mudstones and shales here yield infrequent to rather common 13 to 12.5-million-year-old carbonized impressions of conifer winged seeds and giant sequoia foliage, in addition to evergreen live oaks and many deciduous varieties.

Right--A collector searches for fossil plant remains in the middle Miocene Aldrich Station Formation in an erosion gully along the north side of Aldrich Hill, Nevada. The view is roughly due west.

Images Of Fossil Plants

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Click on the images for a larger pictures. Left--Here is a complete spinose leaf from an evergreen live oak Quercus pollardiana, collected from the middle Miocene Aldrich Station Formation at Aldrich Hill, Nevada. It is practically identical to leaves produced by the modern maul oak, also called canyon live oak, now native to the western Sierra Nevada and the Coastal Ranges of California. The specimen is 30mm long.

Middle--A complete leaf from an evergreen live oak called Quercus pollardiana from the middle Miocene Aldrich Station Formation, Aldrich Hill, Nevada. This particular species of fossil oak is allied with the modern maul oak, Quercus chrysolepis, which is presently native to the western slopes of the Sierra Nevada and the Coastal Ranges of California; note the entire margin (smooth, without spinose indentations) of the fossil leaf. Modern maul oaks can produce on the same tree leaves that are entire and others that are spinose. The specimen is 35mm long.

Right--Two fossil alder cones (the twig-like specimen at the bottom of the image is an unidentified plant fragment) from the middle Miocene Aldrich Station Formation, Nevada; left to right, cones are 21mm 18mm long, respectively. They came from a species of alder called Alnus smithiana, which is similar to the modern Alnus tenuifolia, or the Western American Alder--sometimes called the Mountain Alder.


Click on the images for a larger pictures. Left--This is a leaf fragment from Lyonothamnus parvifolius, the fossil equivalent of the modern Catalina ironwood (Lyonothamnus floribundus) and channel ironwood (Lyonothamnus asplenifolius)--also called Lyon Tree, both now restricted in native habitat solely to the Channel Islands off the coast of Southern California. The specimen is roughly 25mm in actual length and was collected from the middle Miocene Aldrich Station Formation, Nevada.

Middle--A twig from a giant sequoia (Big Tree, called Sequoiadendron chaneyi), measuring 26mm in length, collected from the middle Miocene Aldrich Station Formation, Aldrich Hill, Nevada. It is approximately 13 to 12.5 million years old.

Right--For comparison with the specimen of fossil Big Tree foliage in middle, here is a Big Tree twig plucked from the giant sequoia (Sequoidendron giganteum) we have planted in our back lot; the specimen shown here is 65mm in actual length. Note the distinctive awl-shaped leaves, which also show up well in the fossil specimen in middle.

Click on the images above for larger pictures. Here are four fossil winged seeds from a spruce; all were collected from the middle Miocene Aldrich Station Formation at Aldrich Hill, Nevada. Carbonized impressions of spruce seeds are among the most common fossil plant remains found at Aldrich Hill, but they are maddeningly difficult to identify to a species level. At the upper left is a winged seed that appears to match what the late paleobotanist Daniel I. Axelrod called Picea sonomensis, whose winged seeds are similar to the modern Brewer Spruce (also called the weeping spruce), Picea breweriana, a rather rare variety whose native habitat is now restricted to the Klamath region of northwestern California and adjacent Oregon. The winged seed remains shown at upper right and lower left most closely resemble conifer seed specimens Axelrod called Picea lahontense, which is an extinct species that cannot be compared directly with any living spruce. According to Axelrod, it seems to bear a closest affinity with the larger-coned spruces of eastern Asia, chiefly China, although P. lahontense is most certainly extinct. At the lower right is a winged seed that closely resembles what Dr Axelrod called Picea magna, a variety of extinct spruce whose winged seeds show a general relationship to the living Picea polita, the tiger-tail spruce now native to the volcanic soils of Japan. The specimens at top left and right are, respectively, 12mm and 17mm long; those at bottom left and right are, respectively, 14mm and 15mm in length.

 Fossil List For: Middle Miocene Aldrich Station Flora

Species names in parentheses are closest modern affinities to fossil taxa:

        Equisetum alexanderi
        Thuja dimorpha (plicata)
        Abies concoloroides (concolor)
        Picea magna (polita. neoveitchii)
        Picea sonomensis (breweriana)
        Pinus florissanti (ponderosa)
        Pinus wheeleri (monticola. lambertiana)
        Pseudotsuga sonomensis (menziesii)
        Tsuga sonomensis (heterophyla) 
        Sequoiadendron chaneyi (giganteum) 
        Mahonia marginata (beali)
        Mahonia reticulata (repens)
        Alnus smithiana (tenufolia)
        Symphoricarpos wassukana (oreophilius) 
        Pachystima nevadensis (myrsintes) 
        Quercus hannibali (chrysolepis)
        Quercus simulata (myrsinaefolia) 
        Aesculus ashleyi (parryi)
        Amorpha oblongifolia (californica)
        Sophora spokanensis (japonica) 
        Comptonia parvifolia (asplenifolia) 
        Fraxinus acornia (velutina)
        Platanus paucidentata (racemosa) 
        Rhamnus precalifornica (californica) 
        Amelanchier apiculata (utahensis) 
        Cercocarpus antiquus (betuloides)
        Populus alexanderi (trichocarpa)
        Populus payettensis (angustifolia)
        Populus sonorensis
        Populus subwashoensis (temula. grandidentata) 
        Salix knowltonii (lemmonii)
        Salix payettensis (exigua)
        Burmelia beaverana (lanuginosa)
        Ulmus moorei (crassifolia)
        Zelkova nevadensis (serrata)

My Other Web Sites--both musical and paleontological

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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