Field Trip To Pleistocene Lake Manix, California

Contents for Field Trip To Pleistocene Lake Manix, California:

Introduction Text: The Field Trip Images: On-Site 

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Please note that collecting fossils of any kind--vertebrate or invertebrate--from the Upper Pleistocene Manix Formation is not allowed, except by a special permit obtained from the National Park Service; such a permit is issued solely to individuals with a minimum B.S. degree from an accredited university whose research projects can be fully verified as authentic by the petitioned authorities.

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 Pleistocene Lake Manix

Perhaps it is difficult to picture, but some 450,000 to 18,000 years ago a great fresh water lake covered roughly 83 square miles (236 square kilometers) of the present-day Mojave Desert in southern California. This was ancient Lake Manix, some 200 feet deep at its highest stand, created by a combination of flood waters from the ancestral Mojave River and an increase in precipitation during an interglacial period of the Pleistocene Epoch. Around the lake lived a fascinating variety of now extinct animals, including Dire wolves, mammoths, La Brea storks, Oregon gulls, Shasta ground sloths, and scimitar cats.

Today, the remains of 21 species of mammals and 25 species of birds can be found in the sediments deposited in that relatively long-lived body of water--in addition to abundant ostracods (a minute bivalve crustacean), freshwater mollusks, and skeletal elements from a fish--the extant Tui Mojave Chub.

Geologists have named those Late Pleistocene silts, sands and clays exposed in this part of San Bernardino County the Manix Formation, an Ice Age remnant which now yields an important diversity of nicely preserved vertebrate and invertebrate specimens that provide an invaluable paleontological chapter in the historical geology of the Mojave Desert district.

The fossil mammal bones from the Pleistocene exposures were discovered sometime in the early 1900s by John T. Reed of San Bernardino, California. Reed was an amateur fossil prospector who immediately understood the significance of his find. He showed the bones to a geology student from the University of California, Berkeley--H.S. Mourning--who in turn took the information to the noted paleontologist/geologist John P. Buwalda.

On January 22, 1914, Buwalda published a brief notice of the discovery of vertebrate fossils in the "Manix Beds" (his original name for the rock formation containing the fossils--a name derived from the Manix railroad siding situated near the most fossiliferous exposures of Pleistocene sediments) in the University of California Publications Bulletin of the Department of Geology, volume 7, number 24. This was a true pioneering work, as Buwalda observed in his report that "no reference to Pleistocene lake beds in this region has been found in the literature." Based on six species of mammals described from the lacustrine deposit, Buwalda dated the "Manix Beds" as Pleistocene, although he was unable to establish the exact stage of the epoch from which his vertebrate specimens were recovered. It is interesting to note, though, that professor Buwalda, in this initial reconnaissance investigation of the Pleistocene beds, correctly determined that the primary reason Lake Manix eventually disappeared was due to a downcutting of its outlet in the Afton Canyon region 40 miles east of Barstow. The rush of water through this "breach in the beach" some 18,100 years ago actually created Afton Canyon, a popular scenic attraction on the Mojave Desert today.

In the years following Buwalda's original research, many Earth scientists have studied the fossil-bearing Late Pleistocene sediments that accumulated in Lake Manix. In 1934, Lawrence V. Compton wrote Fossil Bird Remains From The Manix Lake Deposits Of California, an article published in the avian scientific journal Condor, volume 36; perhaps unduly influenced by the presence of some small horse specimens in the fossil fauna, Compton originally thought that the Manix beds might be as old as Late Pliocene, but eventually concluded that they were more likely early Pleistocene in geologic age--a rough estimate later contradicted by more reliable avian and mammalian fossil material from the Manix Formation; today, the Manix beds are universally regarded as Late Pleistocene in age. The third important paper on the subject was Pleistocene Lake of the Afton Basin, California, by E. Blackwelder and E.W. Ellsworth, 1936, American Journal of Science 5th Series, volume 31. Blackwelder and Ellsworth recognized two separate periods of lacustrine deposition. The older of the two lakes disappeared they concluded due to desiccation, while the younger body of water vanished--as Buwalda had claimed many years before--when the overflow channel at Afton Canyon was eventually downcut enough to allow the ancestral Mojave River to flow freely across the land, draining the lake.

More research followed. In 1954, H.H. Winters wrote an important scientific report that concentrated specifically on the fossils of the Manix Formation: The Pleistocene fauna of the Manix beds in the Mojave Desert, California, an unpublished masters thesis for the California Institute of Technology. During his field work Winters collected 12 species of fossil birds which were later (1955) described in detail by Hildegarde Howard in United States Geological Survey Professional Paper 264-J, Fossil Birds From Manix Lake California. In 1968, George T. Jefferson completed an unpublished masters thesis from the University of California, Riverside, The Camp Cady local fauna from Pleistocene Lake Manix. For several years Mr. Jefferson was associated with the George C. Page Museum, La Brea Discoveries, located at the world famous La Brea Tar Pits in Los Angeles, California--a site which contains the greatest accumulation of Late Pleistocene mammals and birds yet discovered on our planet. He has written exhaustively of the fossil fauna of Pleistocene Lake Manix, and in fact formally named and described the Manix Formation in his 1985 paper, Stratigraphy and Geologic History of the Pleistocene Manix Formation, Central Mojave Desert, California, Contributions to Science, number 352, Natural History Museum of Los Angeles County. Jefferson also co-authored the 1982 report, Manix Lake and the Manix Fault Field Trip Guide, Quarterly San Bernardino County Museum Association volume 29, with Jeffrey R. Keaton and P. Hamilton.

In the 1990s, Dr. Norman Meek contributed additional noteworthy scientific investigations of the Manix Basin. See his following references, for example: Geomorphic and hydrologic implications of the rapid incision of Afton Canyon, Mojave Desert, California, Geology Magazine, volume 17; unpublished doctoral dissertation for the University of California at Los Angeles, Late Quaternary geochronology and geomorphology of the Manix basin, San Bernardino County, California, 1990; and New discoveries about the Late Wisconsinan history of the Mojave River, San Bernardino County Museum Association Quarterly, 46(3), p. 113-117, 1999.

The Upper Pleistocene Manix Formation is one of the most famous and paleontologically important fossil-yielding areas in all of the western United States. For this reason, the fossiliferous badlands carved in the Manix Formation were first set aside by the Bureau of Land Management as an Area of Critical Environmental Concern; numerous years later, the area became part of the federally protected Mojave Trails National Monument. This means that it is illegal to remove any fossil from the Manix Formation--vertebrate or invertebrate, for that matter--without a special permit issued by the administrative authorities.

But all interested persons are certainly welcome to visit the region, a classic desert land of harsh extremes and austere beauty. Any particularly well preserved bones or invertebrate remains should be brought to the attention of a professional paleontologist, who will be able to asses their scientific value: this is a paleontologically priceless region. Each fossil specimen secured from the Manix exposures could help write yet another page in the historical geology of the Mojave Desert. It is imperative that professional paleontologists have the opportunity to examine the finds made by those who visit the area; and who knows, you might even have found a species that is new to science.

Probably the best place to examine the Upper Pleistocene Manix Formation is Bassett Point, which includes the area most-studied by paleontologists. Here, the gray to pale-greenish and brownish clays, silts and sands of the Manix Formation are well-exposed along the course of the Mojave River, a bed of parched sand most of the time, devoid of all moisture. Two-hundred thousand years ago, however, that very spot would have been completely submerged beneath the pristine waters of an Ice Age lake. At Bassett Point one stands atop the youngest sediments of the Late Pleistocene strata. Approximately 100 yards (90m) west, in deposits slightly higher in the section, a bed of fresh water mollusks has been dated by the Carbon 14 radiometric age method at 19.1 thousand years old. A fossil horse bone from near the base of the 127 foot-thick (38m) Manix section yielded a radiometric age of roughly 350,000 years (a date not established with the Carbon 14 method, of course, which is accurate only up to around 50 thousand years); this is certainly the oldest vertebrate fossil horizon in the Manix Formation.

Most of the fossil bones, though, have been collected from a narrow three-foot zone in the middle of the formation, vertebrate specimens dated by the Uranium-Thorium equilibrium method at 290 thousand years old. Two additional bone-bearing horizons occur in the Manix Formation, although they yield far fewer specimens than the older zone. One occurs a few feet above the main bone bed and has been dated by the Uranium-Thorium technique at 195 thousand years; the second is found throughout the uppermost 20 feet (6m) of the Manix Formation in strata approximately 60 to 19 thousand years old.

Two widespread beds of fresh water mollusks also occur throughout the Manix Formation. The older of them yielded a Carbon 14 dating of 49 thousand years, while the younger shell horizon, also dated by the famous Carbon 14 radiometric age method, was determined to be 19.1 thousand years ago.

The Manix Formation of San Bernardino County, California, has yielded one of the most significant fossil faunas of Late Pleistocene mammals and birds on the West Coast. Many of the species identified have also been recognized in the incredible tar traps of the famous Brea pits in Los Angeles and McKittrick.

In addition to the mammals and birds, several other varieties of animal life have also been recovered from the sediments of Ice Age Lake Manix. These include five species of ostracods (a minute bivalve crustacean), two species of fresh water pelecypods, nine species of fresh water gastropods, two species of fish (the Tui Mojave Chub and Three-spine stickleback), and one species of reptile (the Western pond turtle).

Among the 25 varieties of fossil birds identified from the Late Pleistocene section are such extinct forms as the Large-footed Cormorant, the Brea Stork, the Small Flamingo, Cope's Flamingo, Shufeldt's American Coot, and the Oregon Gull; living members of the avian fauna include the Arctic Loon, Eared Grebe, Western Grebe, American White Pelican, Double-crested Cormorant, Tundra Swan, Honker, Green-winged Teal, Mallard, Greater Scaup, Common Merganser, Ruddy Duck, Bald Eagle, Crane, sandpiper, a phalarope, a large gull, Golden Eagle, and the Great Horned Owl.

In analyzing the variety of bird fossils in the Manix Formation, it is germane to note that 96 percent of the specimens are considered waterfowl. Also, two-thirds of the living members of the fauna presently prefer to feed exclusively on small fish. From this line of evidence, it appears probable that the Tui Chub represented in the fossil record here provided a substantial diet for many of the birds at Lake Manix. The life habits of living members of the fossil bird assemblage show that the primary Late Pleistocene habitats included open water, sandy beaches and abundant reedy marshlands. Many extant representatives of the fossil bird fauna range at present throughout southern California and can be found seasonally on the Salton Sea and other inland bodies of water; several living species prefer coastal marine conditions or inland areas in the San Joaquin Valley of California.

Among the 21 species of mammals identified from the Manix Formation, the following extinct types can be recognized: a medium-sized ground sloth; the Shasta Ground Sloth; a large ground sloth; a mammoth; the Dire Wolf; a short-faced bear; a scimitar cat; the Western Camel; the Minidoka Camel; a Large-headed llama; an Antique (Ancient) Bison; the small Mexican Horse; and a large Western Horse. Living members of the mammalian fauna include a jack rabbit, a mouse, Coyote, a bear, Puma, Pronghorn, and a Bighorn Sheep.

Plant remains in the Late Pleistocene beds are rare, but a few poorly preserved specimens have been encountered, mainly carbonized wood and leaf fragments that have not appreciably helped to determine the kind of vegetation that once existed here. Better evidence is supplied by fossil pollen found at the Calico Early Man archaeological excavation site near Yermo, California, about 15 miles west of Bassett Point, in alluvial material that correlates with strata in the Manix Formation some 100 to 75 thousand years old. Here scientist S. Peterson recovered pollen specimens from pine, oak, sagebrush, ragweed (woe to American aboriginal allergy sufferers!), goosefoot and juniper. Such plants were probably widely distributed in the moderate uplands bordering Lake Manix.

In an attempt to better understand the Ice Age vegetation of Lake Manix time, scientists have also analyzed the plant remains in packrat middens that date from the Late Pleistocene. Based on the fossil gatherings of such rodents in southern Nevada, Arizona and southeastern California, there is convincing evidence to suggest that modernday woodlands now restricted by altitude were some 3,000 feet (910m) lower during deposition of the Manix Formation. This means that Pinyon pine and juniper, presently kept to a regional minimum elevation of 5,850 feet 1,780m), were in all likelihood thriving at 2,600 feet (790m) 200 thousand years ago in the neighboring Alvord, Cady, Calico and Newberry Mountains. Today these mountains are practically barren of any kind of vegetation.

From the available evidence, it appears that juniper, sagebrush and creosote brush covered the alluvial slopes surrounding Lake Manix. Slightly higher elevations supported a Pinyon pine-juniper-evergreen live oak woodland, while white fir likely formed a dense forest in the Newberry and Ord Mountains at an altitude of 3,950 feet (1,200m); present-day conditions keep white fir a a minimum elevation of 7,150 feet (2,180m). Bordering the lake were marshlands that probably supported reeds, rushes, pondweed, duckweed and cattails. Patches of grasslands apparently existed in the drier flats, much like they do in present-day regions characterized by a similar juniper-oak woodland.

Today, the luxuriant growth of Pleistocene plants has vanished. In their place is an extensive barren badlands of pastel sediments which yield a wealth of fossils. The most commonly encountered mammalian remains belong to the Western Camel (an impressive reconstruction of this creature can be viewed at the George C. Page Museum of La Brea Discoveries in Los Angeles), the Large-headed llama, the large Western horse, the Mexican Horse and the mammoth. Among the birds--whose hollow, delicate bones are miraculously well preserved in the Manix Formation-- the most frequently reported species include the Western Grebe, the Small Flamingo, The American White Pelican, and the Honker.

Specimens of the Tui Chub and Three-spine stickleback, while found scattered throughout the fine silts and sands of the upper half of the Manix Formation, are often concentrated in the middle of the sedimentary section in strata roughly 290 thousand years old. Curiously, the bones and scales from these species of fish are the most commonly encountered vertebrate fossils in the Late Pleistocene beds. The remains are often rather small, however, and even professional paleontologists get down on all fours, with nose to the ground, when prospecting a likely fish-bearing horizon in the Manix exposures.

Also living in ancient Lake Manix were numerous gastropods and pelecypods. Such mollusks are among the most abundant of forms found in the Late Pleistocene section. The two widespread beds crammed with well preserved snails and clams occur near the top of the formation in distinct zones about 18 feet (5m) apart. Their original shell material has been preserved intact, although it is extremely brittle. Both mollusk-bearing beds yield a bewildering mixture of forms that, individually, prefer different fresh water habitats--such as rivers, streams, ponds, lakes, bogs and swamps. Apparently this unusual assemblage of snails and clams resulted from deposition due to flooding. Mollusks from every local habitat were jumbled together by the rising waters of Ice Age storms, then they were transported and dumped into the reaches of Lake Manix by the engorged streams.

Those streams also brought in loads of clays, silts and sands over a period of perhaps 430 thousand years--sediments that contributed to the 127 foot-thick (38m) section presently exposed on the Mojave Desert. Today, it is indeed fascinating and fun to hike amidst the badlands carved in those lake-deposited, loosely consolidated materials of the Upper Pleistocene Manix Formation. The exposed strata have been preserved in an essentially horizontal bedding attitude, and there is a gradual and easily negotiated slope that leads downward from Bassett Point to the outcrops below. With each step taken, you move back thousands of years in geologic time to a lush late Pleistocene landscape of water and green and abundant animal life.

When you visit the 450 to 18 thousand-year-old Manix Formation, take some special time to enjoy the view afforded at Bassett Point. Below is stark desert, a blistered region of subdued hues, a harsh and unforgiving landscape where vegetation is scarce and visible animal life apparently nonexistent. That a great Ice Age lake once covered this land seems improbable, but the fossils in the sediments prove the case--that 290 thousand years ago you would have seen flamingos, pelicans, ducks, eared grebes, gulls, storks, cranes and loons swimming and wading in Pleistocene Lake Manix, a vast 83 square miles (236 square km) of pristine, clear glacier-fed waters that teemed with fish for the hungry birds. Above the lake would circle Bald Eagles and Golden Eagles and Great Horned Owls--large predatory birds, raptors, ready to seize the unwary in their powerful talons.

Amid the surrounding countryside a Shasta Ground Sloth might be seen leisurely browsing on the upper branches of a juniper tree; a pack of hungry Dire Wolves is cutting off a large Western Horse from the herd; and a scimitar cat has just brought down a baby mammoth on a open grassy plain. There is blood gushing from the punctured jugular and the vulturous condors soar high above.

In the distance, a violent storm is developing, a storm that will create a rushing flood of waters destined to sweep along the carcasses of both mammals and birds to the momentarily placid lake; there, the bones will be covered by fine clays, silts and sands, to remain hidden for some 290 thousand years until they are seen for the first time by human eyes in the middle of a great desert.

On-Site Images

A seeker of Ice Age times on the Mojave Desert stands amidst the Upper Pleistocene Manix Formation. Here, the view is looking slightly north of eastward, just downslope from Bassett point, to the eroded uppermost sediments of Late Pleistocene Lake Manix. The gully which runs just behind the individual was loaded with abundant, perfectly preserved skeletal elements from the Tui Mojave Chub, indicating widespread lacustrine (lake) conditions in this part of the present-day Mojave Desert some 19,000 years ago.

The view is roughly eastward from the vicinity of Bassett Point. Common to abundant Tui Mojave Chub skeletal elements weather out of the lake-deposited sands and silts of the Upper Pleistocene Manix Formation within the foreground and middleground of this panorama--in addition to occasional bones from mammals and birds. Shell beds loaded with nicely preserved fresh water gastropods and pelecypods occur just out of sight at right side of photograph.

Photographs Of Fossils

Six fossil fish vertebrae from a Tui Mojave Chub (Gila bicolor mohavensis)--the scale is in millimeters--Upper Pleistocene Manix Formation, San Bernardino County, California. They came from the uppermost few meters of the Manix Formation, so they're likely some 40-to-19 thousand years old; collected long before the Manix Lake Beds were first set aside as an Area Of Critical Environmental Concern and then later included in Mojave Trails National Monument.

Here are six fossil fresh water gastropods from the youngest phases of deposition of the Upper Pleistocene Manix Formation, San Bernardino County, California--they are roughly 19 thousand years old, and all belong to the genus Planorbella. The scale is in millimeters. Specimens were collected long before the Manix Lake Beds were first aside as an Area Of Critical Environmental Concern and then later included in Mojave Trails National Monument.

A camel metapodial (one of the foot bones) in the Upper Pleistocene Manix Formation San Bernardino County, California. Called scientifically, Camelops hesternus; for scale, the geology hammer is 33 centimeters long (almost 13 inches). The vertebrate fossil is lying in the youngest phases of Lake Manix Basin sedimentary deposition, so it's between 40 and 19 thousand years old.

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  • 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.
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  • 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.
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  • 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.
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  • 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.
  • 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.

US Geological Survey Papers (Public Domain)

Online versions of USGS publications I've created

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