U.S. DEPARTMENT OF THE INTERIORBUREAU OF LAND MANAGEMENT
|Hollister Field Office|
The Bureau of Land Management Paleontology Program Objectives are to:
Paleontology is the study of fossils; what fossils tell us about the ecologies of the past, about evolution, and about our place as humans in the world. Paleontology teaches us about the interrelationships between the biological and geological ecosystem components over time.
The BLM considers paleontological data as "constituting a fragile and nonrenewable scientific record of the history of life on earth, and so represent an important and critical component of America's natural heritage." This attitude towards paleontological resources is important because once these resources are "damaged, destroyed or improperly collected, their scientific and educational value may be greatly reduced or lost forever."
The major laws protecting fossils on BLM lands are the Federal Land Policy and Management Act (1976), the National Environmental Policy Act (1969), and various sections of Part 43 of the Code of Federal Regulations.
There is no commercial collection of fossils on Federal lands. Permits for collection are issued by the BLM, primarily for vertebrate fossil specimens (animals with a backbone). Usually no permit is needed for the small‑scale collection of invertebrate specimens (animals without a backbone) as long as you are not collecting in a special use area ‑ like a Wilderness Study Area (WSA) - and you are collecting for personal use.
Paleontological excavation and jacket casting in the Panoche Hills
Check with the BLM office nearest you for permitting regulations and the locations of special use areas and visit the BLM National web page on fossil collection. Local BLM offices might also be able to direct you to known and approved fossil collection areas.
Significant fossil bearing deposits within the Hollister Field Office area occur in the Diablo Range of the Coast Mountain Ranges along the west side of the San Joaquin Valley. Sixty‑five million years ago in what is now the eastern portion of the Field Office area the San Joaquin Valley was part of the Pacific Ocean, and the Coast Mountain ranges were a series of islands that isolated whole groups of organisms. These island residents included many rare and unique animals of the Cretaceous Period and of the Oligocene and Miocene Epochs of the Tertiary Period. Some of the fossils recovered from and/or documented in the Hollister Field Office area include: mollusks, sharks, bony fish, turtles, sea lions, coral, deer, oysters, horses, weasels, whales, rhinoceros, sponges, camels, bears, and dinosaurs.
Research in 2004 involving fossil discoveries from the Path 15 power line project have contributed to a better understanding of the fossil resources in the San Joaquin Valley Temblor Formation. Prior to discovery of the bonebed under a power line tower, the only site producing terrestrial vertebrate fossils from the Temblor Formation was discovered near Coalinga sometime before 1915. Notable aspects of this newly discovered bonebed include the first amphibians, tortoises, birds, rabbits, terrestrial snails, and freshwater snails ever found in the Temblor Formation. A new genus and species of a badger/wolverine-like mustelid was also recovered. Most of the fossils at the new site were primarily terrestrial mammals and freshwater snails that date to the late part of the Middle Miocene Period, approximately 15-16 million years ago.
The fossils collected from the Path 15 project are the first terrestrial vertebrate fossils collected from the Temblor Formation in nearly 70 years. These are the first amphibian, lizard, tortoise, bird, terrestrial snail, and freshwater snail fossils from the Temblor Formation. The most complete shell of a Middle Miocene tortoise ever found in California was recovered from this new site. The avian fauna was also very important; as there is no other non-marine avian fauna of this age in California and the grebe and songbird fossils are some of the earliest known in North America.
View of upper jaw (maxilla) fossil of extinct horse Merychippus californicus
"New Records of Middle and Late Miocene Perissodactyla and Artidactyla from the Western Border of the San Joaquin Valley, Diablo Range, Fresno County, California" - Contributions in Science, Natural History Museum of Los Angeles County No.516 (2008)
Moreno shale is derived from fine-grained sediments deposited in a prehistoric, warm, shallow marine environment during the late Cretaceous (65 million years ago). The formation is approximately 1000 feet thick and exposed as a monocline on the interior edge of the California South Coast Range, bordering the western San Joaquin Valley. The Moreno shale has four distinct members (layers) - from oldest to youngest: Dosados, Tierra Loma, Marca, and Dos Palos. The largest exposures of the Moreno shale formation occur at Panoche Hills and Tumey Hills. Selenite gypsum is also common in the shale.
View of the Moreno Shale soil in the Panoche-Tumey Hills Area.
The Moreno shale formation in the Panoche and Tumey Hills contains the highest diversity of organisms from the late Cretaceous period in the western United States. The formation has yielded numerous specimens of both terrestrial and marine organisms. Since the depositional environment was a shallow sea, many terrestrial organisms - plant and animal - were swept out to sea where they sank to the sea floor along with dead marine organisms. Soft parts of these plants and animals decomposed, leaving hard parts (shells, bone, and wood) to become buried by sediment and fossilize.
The Moreno shale has a rich academic history of vertebrate fossil excavation since their discovery in in 1936. Paleontologists from universities including California Institute of Technology, Stanford University, Los Angeles Museum of Natural History, University of California, California Academy of Sciences, and California State University Fresno intensively surveyed the shale, conduced numerous excavations, and discovered several species wholly new to science.
Flowering plant species diversified enormously during the Cretaceous period, therefore plant fossils from that period are important to understanding the evolution of flowering plants. Flowering plant species are well-represented in the Moreno shale as numerous branch fragments and a few large-diameter fossilized logs.
Moreno Conifer fossil from the Panoche Hills.
Although wood anatomy is well-preserved in most cases it is not aesthetically attractive, having mostly a dull, gray, ashy color and consistency. Some species level identification of plant species from wood anatomy has been possible but very difficult. Broadleaf impressions are extremely rare. Leaf impressions and foliated branch fragments of a species identified as Moreno conifer (Margeriella cretacea) are occasionally found. Fossilized wood from the Moreno shale has scarcely been studied and further study of the fossilized wood will undoubtedly reveal further plant species.
Scientific illustration of the Moreno Conifer species.
Although the area was a shallow sea, seashells are very scarce in the Moreno shale. The microscopic shells of algae (diatoms) are abundant and have been studied in detail. Fossils of fish and sharks are occasional.
By far the best collected specimens from the Moreno shale formation have been those of large reptiles and dinosaurs. Fossils of large vertebrates from the Cretaceous period are extremely rare in California. The Moreno shale has yielded specimens of several large marine reptiles new to science including Plotosaurus bennisonii, Plotosaurus tuckeri, and Plesiotylosaurus crassidens (types of mosasaurs), as well as Morenosaurus stocki, Hydrotherosaurus alexandrae, Fresnosaurus drescheri, and Aphrosaurus furlong (types of plesiosaurs). A few specimens of terrestrial dinosaurs (hadrosaurs; Saurolophus sp.) have also been found.
Most of the specimens now reside in paleontological repositories such as the University of California Museum of Paleontology (UCMP) at Berkeley and the Los Angeles County Museum of Natural History. Fossils from the Moreno shale reveal important clues about species and ecosystems in California 65 million years ago. When skeletons are reassembled, they show what the animal looked like, how it lived, and what it ate.
The reconstructed Morenosaurus stocki skeleton shows its streamlined body form and that its limbs were reduced to paddles, ideal for swimming. Its long, sharp teeth indicate that it was a carnivore and likely consumed fish. Based on anatomy, an artistic reconstruction of the species can then be made. Features such as skin color and texture are not evident from fossils and are left up to the artist who will sometimes use related living species as a model.
Plant species and vegetation types can be interpreted from plant fossils too. The anatomy of fossil plants can often be traced to that of a living species which can then be used as models to create artistic reconstructions.
It is known that at least one conifer species (Margeriella cretacea), one palm species (Palmoxylon sp.), two elm species (Ulminium mulleri, Ulminium pattersonensis), two sycamore species (Plataninium platanoides, Plataninium californicum), one magnolia species (Magnolioxylon panochensis), and one shrub species (Tetracentronites panochensis) grew together. This combination of plants suggests a forest growing in a humid, temperate climate. Some fossilized branch fragments contain spiral indentations around them, which may be evidence of the presence of strangling vines (lianas). Some of the fossilized wood contains growth rings which provides further evidence that the climate had seasonal variability (alternating temperature and/or precipitation).
The end of the age of dinosaurs and large reptiles occurred in the late Cretaceous period, 65 million years ago (Cretaceous-Tertiary is referred to as the "K-T Boundary"). The leading theory on the mass extinction of dinosaurs and large reptiles is a massive meteor impact on the Yucatán Peninsula in Mexico, the 110 mile wide Chicxulub Crater (2,100 airline miles from the Moreno shale formation in California). Fallout from the impact is believed to have resulted in a widespread dust cloud that encompassed the Earth, blocking sunlight vital for plant growth and survival. Sulfuric acid generated from the blast fell back to earth as acid rain and global-scale firestorms resulted from superheated debris. The end of the age of dinosaurs paved the way for the age of mammals.
Scientific illustration of the prehistoric seas and islands in central california 65 million years ago depicting Hadrosaurs and Moreno Conifers on the land with mosasaurs and turtles in the sea.
Iridium is an extremely rare element on Earth but is found in higher concentrations in meteorites. Evidence of the meteor impact is found globally as a thin layer (< 1 inch) of sediment enriched with iridum. The K-T Boundary is represented in the Moreno shale, occuring in an 8 foot thick interval approximately 22 feet above the contact between the Marca shale and Dos Palos shale members.
Since the K-T Boundary dust and debris were deposited in a marine environment at the Moreno shale location, constant movement of sea water largely obscured what is typically less than a 1 inch thick layer in terrestrial deposition scenarios. Evidence of the K-T Boundary in the Moreno shale has been identified from the presence of spherules (tiny glass-like beads) and inferred by the lack of foraminiferan (microorganism) fossils in shale layers above (younger than) the K-T Boundary.
Research in the Moreno shale is ongoing and includes collaborative projects of the Bureau of Land Management with University of California Berkeley, California State University Stanislaus, and California State University Fresno.
Excavations in 2010 include a plesiosaur prepared by Susan Bowman at CSU Stanislaus and a mosasaur to be prepared by Dr. Bob Dundas at CSU Fresno. An extremely rare sea turtle specimen was found in 2008 and is being prepared by Pat Holroyd at UC Berkeley (University of California Museum of Paleontology); only 5 specimens of sea turtles from the late Cretaceous are known from the western United States.
Paleontological Resources Partners with BLM Hollister:
Paleontological Resources Learning Fun: