Geology: Very similar to that of other Ventura fossil sites such as: .
Paleontology: Black fossil bone about 14-15 inches long, which was found in a layer of sand that was cut into by the waves, was submitted on November 18th, 2016.
Other: If you have any input that would help identify the fossil, feel free to contact us and we will update this find.
Directions:
According to this page’s first citation, ” from LA, travel north on the Ventura Freeway (101) towards Ventura. Travel about an hour, north towards Santa Barbara. Exit onto Highway 150 (towards Lake Casitas) and park immediately after leaving Route 101. The fossils are found along the freeway offramp and up the hill above.”
Geology of the Area:
Rincon Point is a famous surfing spot on the border of Santa Barbara and Ventura County. The fossils of Rincon Point are found off a freeway cut that exposes 16 different layers of Santa Barbara Formation strata. Santa Barbara County was underwater for most of Earth’s history, but slowly rose to the surface during the Cenozoic Era, especially as a result of the Miocene dated tectonic movements that created the San Andreas Fault.
Fossils:
Pliocene-Pleistocene dated fossils are abundant in the sediments off the freeway. The fossils are marine fauna including invertebrates such as bryozoa,mollusks, gastropods, and Pecten.
Works Cited:
Gary Kindel, “Fossil Collecting Sites in North America,” (Digital Rockhound’s Companion Site 2009) http://www.digitalrockhound.blogspot.com
“US and Canadian Fossil Sites — Data for California” http://donaldkenney.x10.mx/STATES/CA.HTM
“Offshore Geology of Santa Barbara County” (County of Santa Barbara Planning and Development ) http://www.sbcountyplanning.org
Geology:
The Sespe Wilderness lies within the Transverse Mountain Ranges. The USGS has information on the geological setting of the mountain range province here. More specifically, the Sespe Wilderness and Sespe Condor Sanctuary are mostly within the Topatopa Mountains and foothills. The Topatopa Range is composed of Oligocene-Eocene age sandstones of the Juncal, Matilija, Cozy Dell, and Coldwater Formations. The uplifting of the Topatopa Mountains was chiefly caused by the San Cayetano fault, which was initiated at 1.9 Ma.
The fossils in the Sespe Wilderness are incredibly common and can be found on the trail and in the abundant boulders nearby. Marine shells can be seen exposed on the outside of eroded and smooth boulders, and on the surface of the rotated strata of the foothills.
Paleontology:
A variety of marine invertebrates are common in the area, including mussels, oysters, cephalopods, and other shelled organisms.
Works Cited:
MCKAY, HANNAH. QUATERNARY STRATIGRAPHY AND GEOLOGIC EVOLUTION OF OJAI AND UPPER OJAI VALLEYS, WESTERN TRANSVERSE RANGES, CALIFORNIA. P.2011
These oysters were found on the Huntington trail about 1.0 miles from the Thacher School. They are part of the Topatopa strata, which is dominantly marine in origin. The Topatopa Range is composed of Oligocene-Eocene age sandstones of the Juncal, Matilija, Cozy Dell, and Coldwater Formations. The uplifting of the Topatopa Mountains was chiefly caused by the San Cayetano fault, which was initiated at 1.9 Ma. The fossils were found in slightly consolidated, matrix- and clast- supported, pebble-boulder conglomerate ground from the Topatopa Mountains.
Chunk of mussel-dense rock
Example of Mussel Extracted
The Cenozoic bivalves were likely to have become extinct in the Pliocene mollusc extinction in California and particularly in the Etchegoin Group that occurred due to falling sea levels and the subsequent cooling of California waters. The mussels are dark blue and have a black sheen when wet. The specimens were hypothesized to be composed of calcium carbonate, which was reinforced by a Hydrochloric Acid test which dissolved it. The fossil have the appearance of regular oysters, and are shaped by concave contours.They were found in clusters, each facing random directions. There appears to be no pattern in their orientation or size.
