The great debate rages on. What killed off the dinosaurs, that exceptionally spectacular and successful group of animals that ruled Earth for roughly 165 million years?

There has certainly been no lack of creative speculation to account for their disappearance. Not a few years ago, for example, a body of paleontology experts declared that the agent of doom was a devastating, mysterious disease epidemic peculiar to dinosaurian systems, a deadly plague that decimated the ranks, leaving the ecologic niches wide open for the immune mammals hiding underfoot, patiently awaiting their turn to dominate. Perhaps.

Soon thereafter a consensus developed among many students of paleontology that less exotic factors determined dinosaurian fate--such "mundane" geologic events as gradual changes in climate and geography brought about through the slow, sure drifting of continents over millions of years; an arguably more plausible explanation, one would assume, since such a scenario could have altered the once dino-salubrious environment, leaving it wholly unsuitable for the continuation of the dinosaur dynasty.

Then again, not to be outdone in the ongoing guessing game, one researcher once postulated with pretty convincing argumentation that a "glandular disorder" played a cruel trick on the massive metabolisms of the larger dinosaurs, causing their extinction through some sort of dietary malfunction.

Another fashionable hypothesis of current vogue posits that a tremendous meteorite impact in the neighborhood of the modern Yucatan Peninsula (AKA, the infamous Chicxulub crater) almost instantaneously ignited a world-wide inferno--after which great clouds of sulfur-laden dust (geochemists say that sulfur was readily available in the substantial quantities of gypsum preserved in strata penetrated by the massive bolide) blocked all vital sunlight, thus terminating terrestrial and oceanic photosynthesis, eventually plunging the delicately balanced average temperature of the atmosphere low enough to usher in a short but lethal ice age--exterminating dinosaurian existence.

Whatever the eventual answers to the puzzle might be, there is little argument among earth scientists that the last of the dinosaurs lived on Earth during the late Cretaceous Period of the Mesozoic Era, roughly 66 million years ago.

Rocks dating from this geologic age are of course widely distributed in the western United States. The thickest and most classically fossiliferous exposures occur in Montana, Wyoming, Utah, Colorado and New Mexico, where numerous prize dinosaur skeletons have been discovered--along with paleobotanically important associated fossil floras.

For the most part, though, these fossil remains have been quarried from terrestrial deposits, sedimentary beds that accumulated on land in rivers, lakes, ponds and swamps. Marine-originated Cretaceous strata in Texas, Colorado, Utah, South Dakota, and Kansas bear an abundant molluscan fauna of ammonites, pelecypods, gastropods, belemnites, and baculites (a variety of uncoiled ammonite).

In California, rocks of late Cretaceous age are restricted to the western half of the state. There, they often contribute to the dramatic contrasts in topography of several of the coastal mountain ranges. Excellent exposures of these almost exclusively marine sandstones, siltstones, and shales can be studied in the Santa Ana Mountains (which border the Los Angeles Basin); in the interconnected ranges that stretch northward from Santa Barbara to a few miles south of Point Sur; and in Humbolt County near Eureka, far up in the extreme northwest sector of the state.

One of the more promising California areas amenable to paleontological prospecting lies along the west side of the Great Central Valley: Here, starting just south of Coalinga, a rather thick belt of late Cretaceous detrital strata extends some 300 miles northward to the vicinity of Redding--an impressive Mesozoic Era accumulation within which there are but minor, localized interruptions in the generally conformable stratigraphic sequence.

And despite the undeniable fact that the rocks overwhelmingly represent marine-originated horizons--a lithologically monotonous interbedding of alternating shales, siltstones and sandstones--several sections nevertheless reveal near-shore paleoenvironments where the abundant remains of terrestrial plants and occasional hadrosaur duckbilled dinosaurs can be found in strata whose normally diagnostic fossils include ammonites, pelecypods, gastropods, foraminifers (microscopic shells secreted by a single-celled animal), tube worms, corals, giant sea turtles, and marine reptiles--plesiosaurs and mosasaurs. According to paleoherpetologists, the Moreno mosasaur Plotosaurus bennisoni achieved the highest degree of aquatic adaption of all mosasuars; it died out in Moreno times only 158,000 years before the meteorite strike that many investigators believe abruptly ended the reign of the dinosaur some 66 million years ago.

Within those rocks, a most productive district for hunting late Cretaceous fossil leaves happens to lie within western Stanislaus County, near the westernmost reaches of California's Great Central Valley--east of San Jose. Here, a near-shore interval in an otherwise deepwater deposit of marine mudstones, siltstones and sandstones yields up numerous species of preserved plants that thrived some 68 million years ago amid the very terrain where dinosaurs dwelled.

This especially rich locality occurs at Del Puerto Canyon, just south of Del Puerto Creek in Stanislaus County. It's approximately 40 miles east of San Jose, and while it's indeed possible to travel backroad to the fossiliferous exposures from that South Bay Area community a more accessible route to the general public is via Interstate 5 to County Road J17--the Patterson Exit. As a matter of fact, I independently ran across the fossil leaf site a number of years ago during a paleontological reconnaissance investigation of late Cretaceous sedimentary deposition along the western side of California's Great Central Valley. Much to my great surprise, several years later (earlier in the 21st century), I learned that the geocaching community had also discovered the Moreno plant-bearing locality in Del Puerto Canyon, when an individual in a geocache rockhounding sub-section posted online its GPS co-ordinates, inviting folks to visit and prove that they'd actually found the exact spot by submitting to his web page a photograph of a fossil leaf from the site.

County Road J17 is of course one of innumerable obscure side roads that connect Interstate 5 with a second major north-south thoroughfare through the wondrously endless flatlands of the Great Central Valley--Highway 99. Taken east, J17 slices through rural farmlands to Turlock, where it intersects Highway 99 at a point roughly 15 miles south of Modesto. The J17 turnoff lies 26 miles north of the Los Banos cutoff--State Route 152--and it's 30 miles south of Interstate 580, which heads over to the San Francisco Bay region.

The locality occurs in a roadcut on Del Puerto Canyon Road--a cut that exposes a 10 to 12-foot thick series of buff-brown, gray-brown, and reddish to purple-tinged silstones and sandstones. The roughly 68 million year-old leaves occur in these detrital rocks.

Approached from the east (that is, beginning at Interstate 5), the exposure extends generally northwestward for some 500 feet, but the majority of plants occur within the first half of the section, as explored from east to west. In addition, the better-preserved paleobotanical specimens seem confined to the pale purplish siltstones interbedded in the predominantly coarse-grained, crumbly, ferruginous sandstones.

These leaf-bearing beds represent the youngest Cretaceous-age depositional phases of the upper Cretaceous to lower Paleocene Moreno Formation--here, around 68 million years old. Indeed, the Moreno spans the world-famous K-T boundary. In geologic map terminology, K is the universal symbol for the Cretaceous Period; and T is used to represent the succeeding Tertiary Period, whose initial epoch is called the Paleocene. Beginning with the Paleocene Epoch some 66 million years ago, dinosaurs no longer lived on our planet.

At the Del Puerto Canyon roadcut exposure of the Moreno Formation, several sedimentary layers reveal abundant carbonaceous content. Numerous black specks, blobs, and slivers of macerated plant material, plus carbonized twigs up to two or three inches long constitute conspicuous components in a few of the blocky grayish sandstones. The best preserved leaves are generally found in several thin pale-purplish silstone layers near the middle of the roadcut. Typical late Cretaceous plants one would expect to encounter include walnuts, oaks, figs, alders, laurels, and magnolias--a decidedly modern-appearing angiospermous association that had already begun to colonize with great success the once conifer/cycad/fern dominated Triassic, Jurassic and early to mid Cretaceous Mesozoic Era world.

Patience is the operative attitude to assume at fossil leaf localities. Often, much splitting of the rocks with a geologic rock hammer (or perhaps a wide-blade putty knife) is necessary to recover the better-quality specimens--that is to say, protracted repetitive physical activity that on occasion tasks endurance.

But this is all part of the thrill of potential discovery that accompanies a fossil-hunting excursion. You never know what that next chunk of material pried apart might reveal. And the ultimate rewards of such wonderful late Cretaceous paleobotany here are very much worth the wait.

In addition to the fascinating paleobotany, the fossil-rich strata at this site also reveal an unusual stratigraphic bedding trend. Stand back from the roadcut to note that the terrigenous sediments would appear to stand at "attention"--at a near vertical tilt. Geologists call this special style of outcropping a dip slope, as the surfaces of the bedding planes, or their dip, correspond to the exposed profile of the cut.

After exploring the primary fossiliferous Moreno Formation beds, one may wish to investigate two additional plant-yielding roadcuts along Del Puerto Canyon Road a short distance away. The first lies two-tenths of a mile west of the main paleobotanical place, where upon causual inspection there appears to be negligible variation in the fossil flora--and the leaves remain far less plentiful and not nearly as obvious in the sedimentary rocks. The third locality can be found one mile west of the second site, or 1.2 miles from the first roadcut discussed; here again the fossil plant diversity and associated specimen preservation is just not as rewarding, although some serious dedicated splitting will usually disclose a number of nice leaves.

Even though the upper Cretaceous to Paleocene Moreno Formation yields important terrestrial fossil material--including leaves, petrified wood, carbonized woody structures, and hadrosaur dinosaurs (unless you've obtained a special dispensational permit from Stanislaus County, by the way, one must not collect vertebrate specimens from the Moreno Formation)--the duckbilled fellow Augustynolophus morrisi, for example, is California's state dinosaur (it occurs only in the Moreno Formation), the world-famous geologic rock unit is nevertheless recognized as a marine-originated deposit; taphonomists suggest that on occasion bloated carcasses of Moreno-time dinosaurs floated far offshore before settling to the sea floor, where silts, sands and muds eventually covered the disarticulated skeletal elements, scattered by currents and oceanic scavengers.

Regarding the herbiverous hadrosaur Augustynolophus morrisi, a fascinating paleontological side-story here is that sophisticated high resolution stratigraphic sampling of Moreno Formation foraminfera (tiny shells secreted by a microscopic single-celled organism)--exquisitely sensitive time indicators whose multitudinous species lived and died during specific, restricted moments in geologic time--proves that during deposition of the Moreno Formation, the hadrosaur dinosaurs went extinct a full 1.23 million years before the infamous meteorite impact of 66 million years ago that many investigators identify as the kill-shot which ended the dinosaurian dynasty on Earth.

In the vicinity of the fossil leaf locality at Del Puerto Canyon, such obvious marine specimens as ammonites, pelecypods (including Inoceramus prisms), foraminifera tests (secreted by a microscopic single celled organism), mosasaurs, plesiosaurs, and the bones, scales and teeth of sea going bony fish occur locally. The sensational Moreno Formation shell beds situated south of Del Puerto Canyon--which produce abundant, world-famous specimens of Glycymerita banosensis pelecypods--occur in sedimentary sections considerably more conglomeratic than the finer-grained strata in the Del Puerto Canyon district. This major change in lithologies and faunal content indicates a high energy near shore environment there during later Cretaceous times.

Of course, fossils of terrestrial plants in the Moreno Formation necessarily demonstrate that deposition of the plant-bearing sections occurred in rather shallow marine waters, perhaps in the vicinity of a delta where organic-rich sediments discharged with regularity into the Cretaceous sea.

And speaking of fossil plants--one unique locality (meaning, it's the only one of its kind in the world) in the Moreno yields apatitized wood--that is, petrified material replaced by phosphate minerals, in association with leucophosphite preserved in gypsum-encased nodules. As one might justifiably expect, paleobotanists have had a regular field day with this specific fossil plant occurrence; the apatized wood has been assigned to the modern genus Chrysophyllum, now native to tropical regions throughout the world, one species of which has managed to colonize southern Florida.

An especially informative scientific study that encompasses the Del Puerto Canyon area is Special Report 104, Upper Cretaceous Stratigraphy on the West Side of the San Joaquin Valley, Stanislaus and San Joaquin Counties, California, by Charles C. Bishop, published by the California Division of Mines and Geology in 1970. Included is a superior quality geologic map that fossil enthusiasts will find particularly useful. Not only does it detail the geographic extent of the Moreno and related Cretaceous formations exposed in the region, but it also pinpoints specific fossil localities--a genuine bonus for seekers of Cretaceous paleontology.

At Del Puerto Canyon, the leaf-bearing upper Cretaceous rocks of the Moreno Formation provide a wonderful window into our geologic past; they were deposited some 68 million years ago while dinosaurs still roamed the land. And the fossil plants now preserved in them witnessed the final struggle of dinosaurs to survive, to endure. The leaves you find here knew the thunder of the dying dinosaur.

• The Acoustic Guitar Solitaire Of Inyo: A Cyber-CD: I play 30 covers of some of my favorite songs on an acoustic 6-string guitar; it's all free music.
• Beyond The Timberline--A Cyber-CD: I play 32 selections comprised of covers and original tunes on acoustic 6 and 12-string guitars; it's all free music.
• The Distant Path--A Cyber-CD: I play 32 acoustic guitar covers and original compositions; it's all free music.
• Inyo And Folks--A Musical History--A Quintuple Cyber-CD: My parents and I play 203 selections; it's all free music.
• Acoustic Stratigraphy--A Cyber-CD: I play 34 covers of some of my favorite songs on 6 and 12-string guitars; it's all free music.
• Back To Badwater--A Cyber-CD: I play 32 covers and original compositions on 6 and 12-string guitars; it's all free music.
• All Inyo All The Time: All six of my cyber-cds in one place (includes a quintuple cyber-cd box set); links to all of my solo acoustic guitar playing, in addition to selections my parents and I recorded during the Golden Age of our spontaneous, impromptu recording sessions. Includes an option to stream all 364 selectons; thirteen hours, seventeen minues and forty seconds of music (it's all free music).
• It's A Happening Thing--Music From The Year 1967: All songs that charted US Billboard Hot 100 (#1 to #100) and Bubbling Under (records that charted in positions #101 to #135) in 1967.

• 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.
• 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.
• 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 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.
• 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 Professional Paper 264-J: Fossils Birds From Manix Lake California, by Hildegarde Howard.
• United States Geological Survey Bulletin 1928: Stratigraphy of the Lower And Middle(?) Triassic Union Wash Formation, East-Central California by Paul Stone, Calvin H. Stevens, and Michael J. Orchard.
• United States Geological Survey Professional Paper 483-F: An Unusual Lower Cambrian Trilobite Fauna From Nevada by Allison R. Palmer.
• United States Geological Survey Bulletin 1527: Age Of The Coso Formation, Inyo County, California by C. R. Bacon, D. M. Giovannetti, W. A. Duffield, W. A. Dalrymple and R. E. Drake.