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|Here's a sampler of two representative shark teeth from the world-famous Sharktooth Hill Bone Bed, roughly 16 to 15 million years old--exposed in the western foothills of the southern Sierra Nevada, in the vicinity of Bakersfield, California. They're from the Middle Miocene Round Mountain Silt Member of the Temblor Formation. At left is a tooth from an extinct Mako shark called Isurus planus--in actual dimension, it's 48mm long (almost two inches); at left is a tooth from an extinct Tiger shark called, Galeocerdo aduncus--25mm long (almost an inch).|
Many fossil prospectors across America are familiar with the name Sharktooth Hill. This is an old and venerable locality, where innumerable shark teeth and marine mammal bones have been collected over the years. It is certainly one of the most famous vertebrate fossil sites in the world--a place where roughly 125 species of sharks, bony fishes, sea mammals, sea turtles, marine crocodiles, birds and even land mammals have been found.
The fossils are concentrated in a rather narrow one-to four-foot thick layer in the Round Mountain Silt Member of the Middle Miocene Temblor Formation, which is exposed over several square miles in the erosion-dissected western foothills of California's southern Sierra Nevada. Although the diggings at Sharktooth Hill have historically yielded the most prolific occurrences of the 16 to 15 million-year-old vertebrate material in the Round Mountain Silt, the so-called Sharktooth Hill bone bed continues to provide collectors with nicely preserved fossils wherever it outcrops.
This is indeed fortunate for amateur paleontology students, since Sharktooth Hill presently lies on private property and is in fact a registered national landmark; unauthorized collecting is obviously forbidden at that most famous of sites, but several other fossil-bearing zones in the immediate vicinity can still be explored by interested amateurs--at least by direct permission from the many local landowners, who presently own almost all of the Sharktooth Hill bone bed exposures not included in the Sharktooth Hill paleontological preserve.
And there is certainly no doubt about it--lots of folks over lots of historical time have visited the Sharktooth Hill area to investigate its Middle Miocene marine vertebrate paleontological preeminence.
The history of fossil collecting at Sharktooth Hill goes all the way back to the middle portion of the 19th Century. In August of 1853 geologist William P. Blake reported the occurrence of well-preserved shark teeth and sea mammal bones from the general area of present-day Sharktooth Hill. At the time, Blake, employed by the United States Topographical Corps, was conducting a field survey for possible railroad routes from the Eastern Seaboard to the West Coast. His discovery is generally heralded as the first confirmed report of fossil shark teeth west of the Rocky Mountains. Blake's important collection was eventually studied in 1856 by the legendary Swiss geologist and paleontologist Louis Agassiz, who at the time was one of the leading authorities on vertebrate fossils.
Sometime after Blake's discovery, enthusiastic amateurs began to explore the Middle Miocene deposits in the dusty hills northeast of present-day Bakersfield. Nobody knows for sure who first coined the name "Sharktooth Hill" to describe the rich fossil occurrences, but there is little doubt that the term accurately identifies the most popular type of fossil found there. Even today, in the centuries after the original find by geologist Blake, well-preserved shark teeth continue to attract considerable attention.
As the population of the southern San Joaquin Valley and of metropolitan Los Angeles (only 90 miles south of Bakersfield) began to increase during the latter half of the 1800s, so did the numbers of regular visitors to Sharktooth Hill. From the beginning of its popularity, the site became a mecca of sorts for fossil hunters. Shark teeth and sea mammal remains in the middle of an arid valley, over 100 miles from the Pacific Ocean, became irresistible attractions and have drawn innumerable individuals to this site over the decades.
Perhaps the most famous amateur collector to visit Sharktooth Hill was Charles Morrice, a clerk for the Pacific Oil Company. Morrice became ardently interested in collecting fossil specimens from the bone bed in 1909 during his off-work hours. Over the course of several years he personally excavated hundreds of thousands of shark teeth weighing, literally, several tons. There is a historically valuable photograph of the legendary Morrice in the informative reference volume, History of Research at Sharktooth Hill, by Edward Mitchell (published by the Kern County Historical Society in 1965); Morrice is shown on-site at Sharktooth Hill, by one of his many digs, with a huge bucket filled to the brim with nicely preserved shark teeth of all kinds. At first, Morrice would simply give his finds away to friends, relatives and acquaintances. But he eventually became an indefatigable, scientifically motivated collector, donating his exhaustive collections to museums and universities throughout the world. In recognition of his contributions to science, two extinct animals from the Sharktooth Hill bone bed have been named in honor of Charles Morrice: a shark, Carcharias morricei, and a sperm whale, Aulephyseter morricei. In later years, the two most important amateur collectors in the Sharktooth Hill bone bed were Bob Ernst (who before his passing collected upwards of 2 million vertebrate remains) and Russ Shoemaker, private land owners in the Sharktooth Hill district who donated exhaustive amounts of Middle Miocene vertebrate fossil material to any number of museums and scientific institutions throughout the world.
Although the prolific bone bed at Sharktooth Hill had been known to paleontologists since the 1850s, the first formal scientific investigation of the fossil-bearing layer was not conducted until 1924. That year the California Academy of Sciences initially decided to spend four months in the field analyzing the fossil deposit on-site. But the diggings proved so productive and challenging that the Academy continued to collect there, off and on, through the 1930s. After the preliminary fieldwork was completed, paleontologists required several years to clean, catalog and identify the abundant material recovered. In all, some 18 new species of mammals, birds, sharks, rays and skates were named from the collections amassed.
From 1960 to 1963 a second major scientific study of the Sharktooth Hill bone bed was undertaken, this time by the Natural History Museum of Los Angeles County. To expose an undisturbed layer of the fossil-rich zone, researchers bulldozed away roughly 15 feet of the barren silty overburden. Using whisk brooms and awls, the scientific teams then carefully removed the essentially in-place bones and teeth from the 16 to 15-million-year-old sediments. This was the first time that paleontologists had actually been able to observe firsthand the relationships of the fossils as they lay preserved in the bone bed. Thus, not only were innumerable perfectly preserved bones and teeth recovered, but invaluable information was also gathered on how the remains of the preserved animals came to rest on the silty floor of a Miocene sea. A major highlight of the museum excavations was the discovery of an almost fully intact skeleton of the extinct sea lion, Allodesmus. Since articulated remains of marine mammals are uncommon in the primary bone-bearing zone, such a complete specimen ranks as one of the most significant finds in the history of explorations at Sharktooth Hill. Another mostly complete, articulated Allodesmus was discovered in deposits above the bone bed many years later by the dedicated amateur fossil hunter Bob Ernst, who donated the remains to science--a fine sea lion specimen now housed at the Buena Vista Museum in Bakersfield.
Perhaps the zenith of paleontological investigations at Sharktooth Hill happened during the 1960s and 1970s. Research crews from universities and museums throughout the United States visited the area, carting away tons of excellently preserved fossil material. Amateur interest in the bone bed also increased, and many a Southern Californian was likely first introduced to the rewards of fossil hunting at Sharktooth Hill.
But the steady stream of visitors appeared to be getting out of hand. Much of the precious bone-bearing horizon was rapidly disappearing. Scientists expressed justifiable concerns that, if left unprotected, the most fossiliferous sections of the bone-yielding horizon would soon be obliterated. The proper government officials agreed with this assessment and in May, 1976, Sharktooth Hill was added to the United States Landmark Registry, a designation which protects the locality from unauthorized collectors.
The Sharktooth Hill bone bed has provided paleontologists with the single largest assemblage of Middle Miocene marine vertebrate animal fossils in the world (the famous Miocene Calvert Formation of Maryland also produces many kinds of marine vertebrate remains). The impressive list of marine mammal specimens alone from the Temblor Formation includes dolphins and dolphin-like creatures, porpoises, sea lions, whales, sea cows, walruses, seals and an extinct hippopotamus-like fellow called Desmostylus--a 10-foot-long animal related to the elephant that evidently walked around on the sea floor crushing shellfish with its massive, powerful jaws. Also identified have been extinct large turtles, a marine crocodile, many kinds of bony fishes, and some 20 species of birds--in addition to the astoundingly abundant sharks and rays.
In addition to the marine fauna, several skeletal elements from land mammals have also been taken from the fossil beds. These include a lower jaw of the mustelid (weasel-like) Sthenictis lacota; a lower jaw of the huge amphicyonid, or "beardog" Pliocyon medius; the dog Tomarctus optatus; the three-toed horses "Merychippus" brevidontus and Anchitherium sp.; the rhinoceroses Aphelops megalodus and Teleoceras medicornutum; the tapir Miotapirus sp.; the deer-like dromomercyids Bouromeryx submilleri and Bouromeryx americanus; the protoceratid (sort of a cross between a modern deer and a cow) Prosynthetoceras sp.; and the gomphothere (an extinct proboscidean) Miomastodon sp. Such remains are exceedingly rare, though, and are usually considered anomalies in the local Middle Miocene fossil record. Their presence in proved marine-deposited rocks points to preservation in shallow sea waters, since it is unlikely that the carcasses of land animals could have been transported far from the ancient shoreline before they settled to the ocean floor.
All of these remains lie waiting to be uncovered in the rolling brush-covered western foothills of the southern Sierra Nevada, several miles northeast of Bakersfield in Kern County, California.
One of the better extensions of the fabulous bone bed was for decades a genuinely fun and educational place to visit. Here, shark teeth and various fragmental skeletal elements from a variety of marine mammals constituted the available fossilized assemblage, a place that for many years amateur collectors were welcome to visit; on any given day of the week, for example, one could expect to find at least a handful of folks (on weekends, the numbers of visitors increased exponentially) exploring the prolific Middle Miocene fossil horizon, collecting loads of well preserved shark teeth and generally enjoying their outdoor experience without having to worry about legal restrictions on their fossil-hunting activities. The local law enforcement and BLM authorities left the collectors alone, as long as the area remained free from litter and vandalism, of course. When I last visited the locality, enthusiastic visitors were still allowed to gather Middle Miocene shark teeth and miscellaneous sea mammal bones, but there is no guarantee that the area has remained accessible to unauthorized amateurs. If the site has been formally closed off, make certain that you obey all the rules and regulations: do not attempt to climb over a locked gate, or with reckless disregard disobey No Trespassing signs which may have sprung up to warn visitors that their presence is no longer welcome.
Upon stepping out of one's vehicle to survey the territory, where to search for the fossilized specimens was quite obvious to all visitors. Along the steep to moderately inclined slopes above the parking area one could observe the unmistakable World War I-style infantry entrenchments that, dipping at a low angle of approximately four to six degrees to the southwest, marked the trend of the prospected bone bed. These excavations were made by armies of a different sort: fossil hunters who in their determination to recover shark teeth and marine mammal bones had created a single extended trench along the entire length of the exposed fossiliferous horizon in this immediate area.
The shark tooth-bearing layer averaged roughly one foot thick here, but was often difficult to spot due to the random digging of previous fossil prospectors. It helped to watch for the dark-brown fragmental bones of sea mammals embedded in the pale-gray matrix of the Round Mountain Silt; these were the most common finds in the Sharktooth Hill bone bed exposures, although the perfectly preserved shark teeth remained the prized items sought by the majority of visitors. The best way to locate fossils was to settle into your "battlefield" entrenchment and commence digging. Here, there was just no substitute for good old-fashioned manual labor. Most collectors simply dug into the fossil-bearing zone with a pick or shovel, carefully inspecting each chunk of Middle Miocene material removed from the exposure. Others brought along some kind of screening device--even a riddle (usually employed by gold seekers)--into which they dumped fossil-bearing dirt. After the sands and silts had passed through the fine mesh, any bones and teeth scooped up remained atop the screen, ready to be packed away for safekeeping.
Unfortunately, the fossil zone was not as prolific as at classic Sharktooth Hill, where almost any section of the bone-yielding horizon explored managed to yield abundant perfectly preserved material. Weathered-free fossils were sometimes found, too, especially after a heavy rainy season, before the hordes of eager collectors had descended on the hill for a new season of fossil-finding; at the once-accessible locality, though, freely eroded forms were conspicuously absent. This was best explained by the great numbers of collectors who visited the site each year. Any remains that had naturally washed out of the 16 to 15-million year-old sediments were in all likelihood immediately plucked up and stored away by the lucky few who happened upon them. As this specific locality remained for many years the primary spot where amateurs were still legally allowed to collect fossils from the Sharktooth Hill bone bed, it was not surprising that such easy pickings were nonexistent.
Other than keeping well-hydrated during hot summer days, the major hazard one faced at the fossil locality, and indeed wherever one happened to dig into the Sharktooth Hill bone bed, was exposure to 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 alkaline soils of California's southern San Joaquin Valley: And the region in which the Sharktooth Hill bone bed occurs is known to contain, in places, significant concentrations of the spores which cause this disease. 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 Sharktooth Hill bone bed--and the southern San Joaquin Valley, in general--must be fully aware of the risks involved.
With regard to the direct risk of contracting Valley Fever while digging in areas where the Sharktooth Hill bone bed occurs, a year 2012 posting at the Facebook page of a major commercial, fee fossil dig operation situated on private property sheds at least a modicum of light on the subject:
"Question: How many people catch Valley Fever after digging at your quarries?
"Honestly, more participants have had encounters with rattlesnakes, than have contracted Valley Fever (VF). Nearly all of our participants DO NOT use dust masks while digging. We have had over 2000 diggers on the quarry in the last 18 months, and we only have 3 reported instances of participants contracting VF. That falls well belo...w the Kern County average, and may say something as to the prevalence of the spores in areas we are excavating. We have four quarries open currently, all located below the surface, in fossil beds aged between 14 and 18 million years. This 'soil time-line' predates the emergence of c. immitis by over 10 million years."
So, here's the bottom line, the proverbial upshot--Valley Fever spores definitely exist in California's southern San Joaquin Valley, and Valley Fever can indeed be contracted from digging in the area where the Sharktooth Hill bone bed occurs. The statistic that "only" three individuals in 18 months of supervised digging there have reported contracting Valley Fever may or may not assuage the justifiable concerns of potential visitors.
The Round Mountain Silt Member of the Tumbler Formation, which contains the Sharktooth Hill bone bed (and could harbor fungal spores of Valley Fever--a noncollectible item if there ever was one), apparently accumulated roughly 16 to 15 million years ago in a semi-tropical embayment. This great body of water covered all of the present-day San Joaquin Valley from the Salinas area southward to the Grapevine Grade, just north of Los Angeles. The incredible bone bed was evidently preserved along the southeastern edges of the sea in waters no deeper than about 200 feet--an estimate based on the presence of fossil rays and skates, whose modern-day relatives prefer such relatively shallow depths. It is illuminating to note that all of the living members of the fossil fauna recovered from the bone layer can be found today in Todos Santos Bay off Ensenada, Baja California Norte; the extant marine mammals of the Sharktooth Hill fauna all migrate there during the winter months.
While scientists understand very well the variety of animals that formerly lived in the Middle Miocene Temblor-period sea, they are less certain of what caused restricted preservation in such a narrow bed in a locally unfossiliferous deposit. Although the Temblor Formation does yield moderately common fossil mollusks and echinoids elsewhere in its area of exposure (Reef Ridge in the Coalinga district, for example), the Sharktooth Hill bone bed occurs in sediments that are mysteriously barren of any other kinds of organic remains. In an interval several hundred feet both above and below the bone-bearing horizon there is absolutely no trace of past animal or plant life.
Typically, such a shallow marine environment as is suggested by the bone bed would be expected to include many sand dollars, gastropods, pelecypods and a wide variety of microscopic plants and animals such as diatoms and foraminifers. But such is not the case here. Even after decades of assiduous, dedicated scientific examination, vertebrate animal specimens remain the only diagnostic types of fossil specimens yet recovered in abundance from the Sharktooth Hill bone bed (a few internal casts of gastropod and pelecypod shells have also been reported from the bone bed, in addition to occasional coprolites, invertebrate burrows, and gypsum-coated pieces of petrified wood--none of which is particularly significant or diagnostic, except to say that such occurrences support the idea that the bone bed formed in relatively shallow waters).
Such an unusual abundance of diverse species of marine mammals, sharks, birds, rays, skates and even land mammals requires a unique mechanism of preservation. Clearly the curious mixing of both land and marine vertebrates in the same layer points to an as-yet incompletely understood set of circumstances. Needless to report, ever since the bone bed's discovery on that summer day way back in 1853, investigators have wondered just what events could have created such a remarkable concentration of vertebrate remains in a narrow horizon, to the exclusion of all other marine invertebrates normally associated with a shallow-water environment.
Several ideas have been advanced to explain the rare occurrence.
One of the earliest explanations was offered during the first quarter of the 20th Century by paleontologist Frank M. Anderson of the California Academy of Sciences. Anderson suggested that violent volcanism in the region poisoned the Miocene waters with ash and noxious gasses, causing the sudden extinction of the fauna. While it is true that widespread volcanic activity occurred in the Middle Miocene of the present-day San Joaquin Valley, there is no direct evidence to suggest that the Sharktooth Hill fauna was adversely affected by it.
A second hypothesis states that during the Middle Miocene, the bay in which the Sharktooth Hill animals lived became landlocked. As the waters gradually evaporated the unlucky inhabitants were doomed to try to survive in an increasingly smaller area, until at last the creatures succumbed, thus creating a narrow zone in which their skeletal and tooth remains were concentrated.
Yet another explanation concerns the "red tide" phenomenon. Occasionally, a toxin-producing marine microbe multiplies so rapidly that it kills smaller fish by the millions. The organism contains a minute amount of a potent poison that can be easily concentrated in the food chain. Larger fish consume the smaller types that feed on the lethal organism until, eventually, all of the fish are killed.
An additional once-popular proposal was that the Middle Miocene Sharktooth Hill area was a great calving ground for marine mammals, an irresistible attraction for sharks who seasonally feasted on the animals gathered there to give birth. Unfortunately, there is a paucity of juvenile sea mammal bones in the deposit--not the amount one would reasonably expect to find preserved in the Round Mountain Silt Member of the Temblor Formation had the area witnessed for thousands upon thousands of seasons youngsters cavorting in the same warm waters that held their predators--the sharks.
Other possible mechanisms of deposition proposed for the famed bone bed are turbidity currents--which are masses of water and sediments that flow down the continental slope, often for very long distances. Presumably, the carcasses of sea and land animals were caught up in such underwater sediment flows, their bones transported for considerable distances before the remains dropped out of suspension in a submarine canyon, far removed from the Middle Miocene shoreline. Perhaps favoring this explanation is the fact that many of the vertebrate remains from the bone bed reveal obvious signs of wear and tear, suggesting some degree of transport and agitation prior to their eventual burial. As a matter of fact, this is the one specific scenario of bone deposition that most closely matches the evidence; indeed, it's the single most widely accepted method by which literally millions of sea mammal bones and shark and ray teeth could have possibly been preserved in such a narrow interval, to the exclusion of virtually every other kind of marine life.
This is but a sampling of the ideas proposed to account for the Sharktooth Hill bone bed. Unfortunately (for the theorists who suggested them), all but one of the above proposals--the turbidity current idea, specifically--are quite simply put flat-out wrong. They have been disproved, falsified. Over the years, there have probably been as many hypotheses advanced as there are scientific speculators to invent them. Suffice it to say that no one single explanation, save the turbidity current proposal, has yet been delivered to answer all the questions posed by this famous bone bed of the Middle Miocene.
In early 2009, though, some researchers claimed that the problem had been solved once and for all. The "definitive" explanation--as published by The Geological Society Of America in a paper entitled, "Origin of a widespread marine bonebed deposited during the middle Miocene Climatic Optimum" by Nicholas D. Pyenson, Randall B. Irmis, Jere H. Lipps, Lawrence G. Barnes, Edward D. Mitchell, Jr., and Samuel A. McLeod--is that the Sharktooth Hill Bone Bed accumulated slowly above a local disconformity over a maximum of 700 thousand years due to sediment starvation timed to a major transgressive-regressive cycle during middle Miocene times 15.9 to 15.2 million years ago. The upshot here, according to the authors, is that the world-famous bone-bed is not the product of a mass dying, neither is it the inevitable result of red-tide poisoning, nor the remains of animals killed by volcanic eruptions, nor the preservations of vertebrates through the concentrating action of turbidity currents--not even the site of a long-term calving region where sea mammals birthed and sharks hunted can fully explain the fabulous bonanza bone layer. The Sharktooth Hill Bone Bed came about, the scientists claim, over thousands of years due to slow, steady bone accumulation during a period of geologic time when very little clastic sedimentation (sands and silts and muds) occurred.
Perhaps this new research has indeed finally resolved the mysteries surrounding the deposition of likely the greatest concentration and diversity of fossil marine vertebrates in the world. The turbidity current idea still holds water (pun intended) for many, though, and will likely remain a lasting viable explanation for many folks in the paleontological and geological communities.
Research on the Sharktooth Hill area has been exhaustive, to say the least. Reference materials on the subject abound. Probably the single best book to consult is the aforementioned History of Research at Sharktooth Hill, Kern County, California, by Edward Mitchell. Other worthwhile works include Birds from the Miocene of Sharktooth Hill, California, in Condor, Volume 63, number 5, 1961, by L.H. Miller; Sharktooth Hill, by W.T. Rintoul, 1960, California Crossroads, volume 2, number 5; and the July 1985 issue of California Geology, published by the California Division of Mines and Geology, in which an excellent article appears entitled, Sharktooth Hill, Kern County, California, by Don L. Dupras.
The once-accessible locality used to make a terrific substitute for Sharktooth Hill. While the fossil remains were obviously not as plentiful as at the more-famous site, amateur collectors and professional paleontologists alike continued to find many beautifully preserved shark teeth and marine mammal bones in the fabulous Sharktooth Hill bone bed. It is a world-class paleontological deposit which has yielded some 125 species of vertebrate animals from the Middle Miocene of 16 to 15 million years ago--a time when a tranquil semi-tropical sea similar to Todos Santos Bay off Ensenada covered the present San Joaquin Valley. It was a time when the ancestors of great white sharks lived where vast fruit orchards now grow in the agriculture-rich Great Central Valley of California.
|Click on the image for a larger picture. A Google Earth Street car perspective that I edited and processed through photoshop. Here's the place paleontological dreams were made of. This is Sharktooth Hill, proper--actually, the eastern-facing front of it--that tallest "peak" at upper center. It's all now a federally protected US national registered landmark, created in May 1976. You can't collect there any longer. But several still-accessible places in the general vicinity continue to draw visitors to the Middle Miocene vertebrate fossil bonanza. Narrow "band" along the upper slopes at center, stretching to the left, is a single extended World War I-style infantry trench, where innumerable collectors over the ages settled into their "fossil fox holes" and commenced digging.|
|Click on the image for a larger picture. A Google Earth street car perspective that I edited and processed through photoshop. The view is just slightly south of due west. Here's where it all began for many a paleontology enthusiast--the traditional entrance to the Sharktooth Hill cornucopia of Middle Miocene fossil wealth. It's now closed off, of course, because Sharktooth Hill, proper, is a US Registered National Landmark, established in May, 1976. For decades, many a person "cut his paleontological teeth" on the abundant shark teeth that occur there in the Middle Miocene Round Mountain Silt Member of the Temblor Formation, roughly 16 to 15 million years old. Obvious evidence of the old World War I-style military trenches, the fossil fox holes if you will, can be seen dead straight ahead, and along the upper slopes at right.|
|Click on the image for a larger picture. A Google Earth street car perspective that I edited and processed through photoshop. A view directly westward. At left was the turnoff spot for what used to be a rather popular place to find shark teeth and miscellaneous marine mammal bones in the Middle Miocene Round Mountain Silt Member of the Tumbler Formation. Faint evidence of a major extended fossil trench can seen at upper dead center of image, below the "peak."|
|Click on the image for a larger picture. This was once a popular spot for folks to come on in and collect all the shark teeth and miscellaneous marine mammal bones they wanted from the Middle Miocene Round Mountain Silt Member of the Temblor Formation. Where to look for the paleontological material was not difficult to figure out; the unmistakable World War I infantry-style trench along the hillside certainly marks the spot.|
|Click on the image for a larger picture. A seeker of the Temblor Sea examines the exact horizon where all the shark teeth and marine mammal bones lie in the Middle Miocene Round Mountain Silt Member of the Temblor Formation, at a once-popular locality several miles northeast of Bakersfield in the western foothills of California's southern Sierra Nevada.|
|Click on the image for a larger picture. A photograph courtesy geologist/paleontologist Dr. Chuck Ciampaglio of Wright State University in Dayton, Ohio. The university group is digging for paleontological goodies at a commercial fee quarry in the Middle Miocene Round Mountain Silt Member of the Temblor Formation.|
|Click on the image for a larger picture. An image courtesy a group that goes by the online name "blackriverfossils." The folks are digging for fossil specimens at a commercial fee quarry in the Middle Miocene Round Mountain Silt Member of the Temblor Formation.|
|Click on the image for a larger picture. An image courtesy a group that goes by the online name "blackriverfossils." An enthusiastic fossil hunter is caught in the act, wielding a pick to help expose the shark teeth and marine mammal bones at a commercial fee quarry in the Middle Miocene Round Mountain Silt Member of the Temblor Formation.|
|Click on the image for a larger picture. A photograph courtesy an enthusiastic fossil hunter named Sherry Anderson, seen here "solving the riddle." She's using a riddle (a device often employed by gold seekers) to sieve through smaller debris, hoping to leave the prized sizable shark teeth and marine mammal bones remaining in the receptacle.|
|Click on the image for a larger picture. An image courtesy a person who goes by the online name of "fossilhunter51." That single extended World War I-style infantry trench running along the hillside marks the precise trend of the Sharktooth Hill Bone Bed in the Middle Miocene Round Mountain Silt of the Temblor Formation, roughly 16 to 15 million years old. Note the surgical mask, worn in deference to Valley Fever fungus spores that infest the uncultivated soils of California's southern San Joaquin Valley. Valley Fever fungus spores are also endemic to California's Mojave Desert, San Fernando Valley, Santa Clarita Valley, and Coachella Valley--not to mention central to southern Arizona, southern Nevada, parts of New Mexico, southwestern Utah, and west Texas.|
|Click on the images for larger pictures. Photographs courtesy a person who goes by the online name of "fossilhunter51." A couple of dedicated paleontology diggers have established residence in one of the "fossil fox holes" in the Middle Miocene Round Mountain Silt Member of the Temblor Formation. Note the surgical masks, worn in deference to Valley Fever fungus spores that infest the uncultivated soils of California's southern San Joaquin Valley. Valley Fever fungus spores are also endemic to California's Mojave Desert, San Fernando Valley, Santa Clarita Valley, and Coachella Valley--not to mention central to southern Arizona, southern Nevada, parts of New Mexico, southwestern Utah, and west Texas.|
|Click on the image for a larger picture. Image is courtesy a group that goes by the cybername "blackriverfossils." This is a freshly dug mako shark tooth from the Middle Miocene Round Mountain Silt Member of the Temblor Formation, about 16 to 15 million years old.|
|Click on the image for a larger picture. The photograph is courtesy a person who goes by the online name of "wildjed." This is a freshly dug mako shark tooth from the Middle Miocene Round Mountain Silt Member of the Temblor Formation, approximately 16 to 15 million years old.|
|Left to right--Teeth of extinct Mako sharks from the Middle Miocene Round Mountain Silt Member of the Temblor Formation, approximately 16 to 15 million years old. Specimen at left is 43mm long--called scientifically, Isurus planus. Shark tooth at right is Isurus hastalis--52mm long.|
|Left and right--Both sides of the same tooth of an extinct Mako shark from the Middle Miocene Round Mountain Silt Member of the Temblor Formation, approximately 16 to 15 million years old. Specimen is 40mm long--called scientifically, Isurus planus.|
|Left and right--Teeth of an extinct Tiger shark from the Middle Miocene Round Mountain Silt Member of the Temblor Formation, approximately 16 to 15 million years old. Called scientifically, Galeocerdo aduncus. Both are 27mm long.|
|Left and right--Both sides of the same tooth of an extinct Mako shark from the Middle Miocene Round Mountain Silt Member of the Temblor Formation, approximately 16 to 15 million years old. Specimen is 35mm long--called scientifically, Isurus planus.|
|Left and right--Both sides of the same tooth of an extinct Tiger shark from the Middle Miocene Round Mountain Silt Member of the Temblor Formation, approximately 16 to 15 million years old. Specimen is 12mm long--called scientifically, Galeocerdo aduncus.|
|Left and right--Both sides of the same tooth of an extinct Mako shark from the Middle Miocene Round Mountain Silt Member of the Temblor Formation, approximately 16 to 15 million years old. Specimen is 28mm long--called scientifically, Isurus planus.|
|Left to right--Teeth of two different species of extinct Mako sharks from the Middle Miocene Round Mountain Silt Member of the Temblor Formation, approximately 16 to 15 million years old. Specimen at left is called Isurus hastalis.Tooth at right is called scientifically, Isurus planus. Specimens are 20mm and 22mm long, respectively.|
|Left and right--Both sides of the same tooth of an extinct Mako shark from the Middle Miocene Round Mountain Silt Member of the Temblor Formation, approximately 16 to 15 million years old. Specimen is 25mm long--called scientifically, Isurus planus.|
|Left and right--Both sides of the same tooth of an extinct Mako shark from the Middle Miocene Round Mountain Silt Member of the Temblor Formation, approximately 16 to 15 million years old. Specimen is 37mm long--called scientifically, Isurus planus.|
|Left and right--Both sides of the same tooth of an extinct Mako shark from the Middle Miocene Round Mountain Silt Member of the Temblor Formation, approximately 16 to 15 million years old. Specimen is 26mm long--called scientifically, Isurus planus.|
|Left to right--Shark teeth from the Middle Miocene Round Mountain Silt Member of the Temblor Formation, approximately 16 to 15 million years old. Specimen at left is from an extinct Tiger shark called Galeocerdo aduncus. Tooth at right is from an extinct Mako shark called scientifically, Isurus planus. The shark teeth are 25mm and 48mm long, respectively.|
|Click on the images for larger pictures. Here is the take from a three-day fossil collecting expedition by a person named "thornsley" to the world-famous middle Miocene Sharktooth Hill Bone Bed, Round Mountain Silt Member of the Temblor Formation (roughly 16 to 15 million years old), Kern County, California; middle image is from day 2. An individual who goes by the cyber-name "thornsley" found all the specimens here depicted, and uploaded to YouTube several views of his extensive Sharktooth Hill Bone Bed collections on February 1, 2012. These are screen captures from thornsley's YouTube video that I edited and processed through photoshop.|
|Click on the images for larger pictures. Here are three screen captures of huge Carcharoles megalodon ("meg'--likely grew to 50 feet in length) shark teeth I edited and processed through photoshop, all taken from a specific video episode of "California's Gold"--a long-running (early 1990s to 2012) PBS program hosted by the late Huell Howser--about the Sharktooth Hill Bone Bed, middle Miocene Round Mountain Silt Member of the Temblor Formation (roughly 16 to 15 million years old); originally telecast on November 8, 2006. The "meg" specimens reside in world-famous Buena Vista Museum Of Natural History in Bakersfield, California, only a few miles from the Sharktooth Hill diggings. Image at far right depicts a reconstruction of the "meg's" monstrous mouth, lined with outrageously large teeth that envelope a modern-day shark for scale. Click Here to watch in its entirety the Huell Howser "California's Gold" episode about Sharktooth Hill.|
Click on the images for larger pictures. I edited and processed all three screen captures from a video uploaded to YouTube on April 22, 2012, by "blackriverfossils." All fossils were collected from the middle Miocene Round Mountain Silt Member of the Temblor Formation, Sharktooth Hill Bone Bed, Kern County, California (approximately 16 to 15 million years old).
Left to right: Teeth from the extinct Mako shark, Isurus planus; middle--teeth from the extinct Mako shark, Isurus hastalis; far right--teeth from the extinct Tiger shark, Galeocerdo aduncus.
In addition to my many Web pages pertaining to matters paleontological and geological, I also have sites up and running that feature my solo, acoustic, instrumental 6 and 12-string guitar playing--in addition to songs I have recorded with my parents over the years (family music) And it's all free music--for listening and for downloads of the mp3 files.
Jump on over to The Acoustic Guitar Solitaire Of Inyo--A Cyber-CD for 30 covers of some of my favorite songs--all played on a 1976 Martin D-35 guitar.
For 32 mp3 selections of original compositions and covers of some of my favorite songs--all played on a 1968 Stella 12-string guitar, a 1976 Martin D-35 guitar and a Sigma DMISTCE guitar, head on over to Beyond The Timberline--A Cyber-CD .
At The Distant Path--A Cyber CD listen to me play 32 covers and original compositions on a 1976 Martin D-35, a Sigma DMISTCE 6-string guitar and a 1968 Stella 12-string guitar.
Over at Inyo And Folks--A Musical History I've created a page that features 118 songs I recorded with my parents--all played on acoustic 6 and 12-string guitars, banjo, kazoo, maracas, and tambourine.
Go to Acoustic Stratigraphy: I play 34 covers of some of my favorite songs on acoustic 6 and 12-string guitars.
Back To Badwater--A Cyber-CD: I play 32 covers and original compositions on 6 and 12-string guitars.