Marble Mountains

Geology of the Area:

The mountains contain a rich outcropping of the Latham shale, known for its diversity of lower Cambrian fossils. The fossils are approximately 518 million years old. The Latham shale borders the Cadiz and Chambless Formations, both named after the small towns nearby. However, the land has become part of a nationally preserved area, so the BLM recommends only one trilobite per person.

Paleontology:

The most common fossils in the shale are trilobites of the Olenellina genus, which are distinguished by their lack of facial structures, and the cephalon or head molted as a single piece. However, brachiopods including some of the earliest articulate brachiopods (meaning they have hinge teeth) have been found in the Latham shale. Hyoliths, trace fossils, and very rarely an Anomalocaris specimen are in the shale at the Marble Mountains.

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Directions:

According to the Bureau of Land Management, “This area can be found by taking historic route 66 to the town site of Chambless then taking Cadiz Road approximately 4 miles south.  At this point  the road turns sharply to the left (east) You will see Cadiz Farms housing on the left side of the road. Continue on east for two miles and just before reaching the rail road crossing turn north on Route (Rt.) NS376 for .4 miles at the intersection with Rt. NS299 drive east for .2 miles. your final turn will be north on NS380 for .7 miles park here near the base of the mountain and hike west to east along the wash.  Hiking up the mountain and looking down hill will allow you to see where others have excavated pits in the shale and help indicate where fossils have been found.”

Works Cited:
Ben Waggoner, “The Marble Mountains,” (UC Berkeley 2000) <http://www.ucmp.berkeley.edu/cambrian/marblemts.html>

“Trilobites in the Marble Mountains, Mojave Desert, California,” <http://inyo.coffeecup.com/site/latham/latham.html>

“Needles Field Office Rock Hounding,” (Bureau of Land Management 2015) <http://www.blm.gov/ca/st/en/fo/needles/rock.html>

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Antelope Creek

Geology of the Area:

Antelope Creek is an outcropping of the Chico Formation, a geological strata found in Northern California and Southern Oregon containing fossils of the Campanian age in the Cretaceous period. Dinosaur fauna have been recovered from the area, but Antelope Creek mainly contains mollusks.

Paleontology of the Fossils:

Fossils found near Antelope creek consist of Santonian-Campanian ammonites and inoceramid bivalves. Additionally, Hyphantoceras venustum, Baculites capensis, Bostrychoceras elongatum, Inoceramus schmidti and Baculites chicoensis have been found in the area.

 

Works Cited:

J.W. Haggart, “Upper Cretaceous (Santonian-Campanian) ammonite and inoceramid biostratigraphy of the Chico Formation, California,” (Cretaceous Research 1984) <http://www.sciencedirect.com/science/article/pii/S0195667184800208&gt;

 

Shell Creek

Geology of the Area:

The area contains Cenezoic marine strata, which is part of the Temblor Formation.

The Fossils:

In the cliffside just off the road are clams, sand dollars, and Oysters, likely dating to the Miocene or Pliocene epoch.

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Shark tooth Hill

One of the most well known and prolific fossil sites in California, Shark tooth Hill is a reliable source of shark teeth and the fossils of over 175 marine species.

Geology of the Area:

The area was a shallow extension of the Pacific extension during the Miocene epoch, or approximately 12-15 mya, and thus harbored a variety of marine mammals, sharks, birds, rays, skates and even land mammals.

Theories for the strata’s dense fossil record include 1) neighboring volcanic activity poisoned the bay with ash and noxious gases, causing a mass extinction of the organisms, and 2) the bay became landlocked during the Miocene epoch, rendering the inhabitants unable to escape as the waters slowly evaporated in the Pliocene epoch.

Fossils:

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Gaviota Beach

Geological History of the Area:

The area of the Gaviota and El Capitan State Beaches contain a series of folds such as the Gaviota Offshore Fold trend which suggests the area is by the Eagle fault and has experienced pressure. Six hydrocarbon (oil) seeps have been found at the El Capitan- Gaviota shelf. During early Miocene time, calcareous plankton dominated this basin fill, but by the middle Miocene, the expansion of the East Antarctic ice sheet led to intense upwelling in eastern boundary current areas. The shelf from which the specimens were collected from is part of the Monterey formation and is riddled with a series of marine gullies. The beach-bordering segments are part of the El-Capitan-Gaviota Continental Shelf.

Fossils:

Near Los Padres Wilderness

 

Geological History of the Area:

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.

Mussels Woolly Booger

Chunk of mussel-dense rock

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Example of Mussel Extracted

 Paleontology of the Fossil:

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.

Works Cited: McKay, Hannah. Quaternary Stratigraphy and Geologic Evolution of Ojai and Upper Ojai Valleys, Western Transverse Ranges, California. p.2011