Society, CA. Muenster, G. In Beitrage zur Petrefacten - Kunde. Sanchez, F. Welton, B. Berkley, pp. Wood II, H.. Nomenclature and correlation of the North American continental Tertiary. Related sites to visit: Tanaka Takeshi's Sharktooth Hill page. Ron Blakey's website on the stratigraphy of the Southwestern US. If you can provide feedback or help us with this effort, contact Jim Bourdon using the below email link.
Taxa sometimes attributed to the fauna, but which can't be substantiated, will include this icon. Parasymphyseals are relatively common in the fauna, but complete anterolaterals are uncommon to scarce. Notorynchus sp - Sevengill shark. Notorynchus was originally reported on this page, however it is now thought that this genus may not be present in the STH fauna.
The presented example may have originated from another horizon or is a mesio-distally compressed Hexanchus lower. Some prefer the more conservative Squalus sp. These teeth are quite abundant in the fauna.
Based on studied material, these teeth are relatively common and are easily confused with male dasyatid teeth or are thought to be from skates, unless observed under magnification. There appears to be no evidence of Carcharias teeth in the STH fauna. Reports to the contrary likely result from specimens found in the Olcese Sand where this tooth-design is somewhat common.
Megachasma sp - Megamouth shark. These West coast teeth are significantly different than Lee Creek specimens and the extant species; possibly a different genus or species. These teeth are deemed a common component of the fauna. Jordan deemed these teeth different from their right coast counterparts erecting Carcharodon branneri. They are abundant in the STH fauna. Cosmopolitodus sp serrate, a. The accompanying specimen although purported from the fauna is more likely from another horizon or location.
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 ; 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 s, the first formal scientific investigation of the fossil-bearing layer was not conducted until 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 s. 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 to 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 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 s and s. 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, , 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 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.
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 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 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:.
We have had over diggers on the quarry in the last 18 months, and we only have 3 reported instances of participants contracting VF. That falls well belo 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. 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. A Hooked White shark tooth fossil freshly exposed from the formation. Valley Fever is a lung infection caused by breathing in fungal spores called coccidioides. These microscopic spores occur in the ground around Bakersfield and other parts of the Southwest. When the ground is disturbed, a person may breath in these spores and become infected.
Valley Fever is a serious illness that you don't want to contract. When digging for fossils in Bakersfield, consider wearing a respirator or dust mask to prevent dust and possible spores from entering your lungs. Elam T and Wilkerson G. Robert Reynolds, April, , pp. Article Here Dupras D. California Geology, July , p.
Prothero, D. Hyndman This roadside Geology series is a must for anyone that does road trips! This one gives a great, easy to understand, overviews of the Geology on Northern and Central California. This newer edition has full color maps, photos, and illustrations. There are GPS coordinates, locations, and explains all the geologic oddities you may drive by. It contains maps, descriptive texts, and both Color and black and white photos of 80 collecting sites.
Plus, it's from , so the sites are still there! Large lower fossil shark tooth from Sharktooth Hill - Carcharodon planus. All attendees must be museum members. Diggers will be allowed to keep all teeth including megalodon teeth and fossils with the exception of rare scientifically significant assemblages or articulated fossils. For details go to Sharktoothhill.
More Coronavirus coverage. Login Subscribe. Thank you for reading! Sign Up.
0コメント