Rincon Point

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

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Topanga Canyon

Geology:

Topanga Canyon is part of the Topanga Canyon Formation. It contains middle Miocene sandstone and siltstone.

Paleontology:

The sediments contain large quantities of gastropods and pelecypods (most are shell prints). It is recommended to go after a rain when the fossils have been washed (at least partially) out of the matrix.

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Directions: 

“from the Ventura Freeway (in the San Fernando Valley), get off at the Valley Circle/Mulholland Drive exit Turn left onto Valley Circle, cross over the freeway and proceed onto Mulholland Drive. Turn right onto Valmar Avenue — Valmar becomes Old Topanga Canyon Road. At Mulholland Highway, bear right and prepare to turn left back onto Old Topanga Canyon Road in 1/8 mile. Turn left and proceed up Old Topanga almost a mile, past the point where the road switches back upon itself. From this point until the top of the hill, you will encounter fossiliferous road cuts on your right. The first embankment contains a massive oyster reef.” (see first citation for source)

Works Cited:

Sam Park, “Fossil Collecting in California” (The Fossil Forum 2008) http://www.thefossilforum.com

“Topanga Canyon fossils,” (Rockhound Blog October 12, 2006) http://www.rockhoundblog.com

Centerville Beach

Geology of the Area: Centerville Beach is part of the Rio Dell Formation, giving it very similar geological history to the Scotia Bluffs nearby. The sedimentary rocks were once a mud rich layer that was deposited on the edges of a shallow sea during the Pleistocene epoch. Look for layers of grey unconsolidated mud, which will be fossiliferous and have shell fossils protruding from the surface. Low tide is the best time to look for fossils on a beach.

Paleontology/ Fossils Found: Moon Snail, Giant Pacific Scallop, Clam, Pandora shell, Cockle, Snail, Channeled Dogwinkle, and other fossils can be easily found on the cliffside of the beach.

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Works Cited:

Leslie Scopes Anderson, “Unearthing Evidence of Creatures from Deep Time,” (Humboldt U 2011) www2.humboldt.edu

Ellin Beltz, “Fossil Localities – Humboldt Bay Area,” (Field Trips by Ellin Beltz 2008) http://www.ebeltz.net

Scotts Valley

Geology: Being within the Santa Cruz Mountains in the Central Coast Ranges, Scotts Valley is a geologically active region under the influence of multiple fault lines. The valley’s bedrock is part of the Purisima Formation. Fossils obtained in the area are likely part of the Santa Margarita Sandstone. According to the Scotts Valley Town Center, “The Santa Margarita Sandstone generally consists of massive, fine- to medium-grained sandstone of upper Miocene geologic age. The Santa Margarita Sandstone forms a distinctive formation of white and yellow sand that can be observed in cliffs around the area”.

Paleontology: Marine fossils are very prevalent in the area, and it is a common area for fossil collectors to visit. Shark teeth (Mako, Megalodon, etc), dolphin, whale, sea cow, and walrus bones, and sand dollars have been found in the area. Sand dollars are especially common and should be fairly easy to spot. Here is a collection of photos of fossils recovered from the area from the Land Trust of Santa Cruz County. Recently, a four million year old whale fossil was discovered in the area. The find was covered by the article, “Whale Fossil Uncovered in Scotts Valley”.

Directions to Sand Dollar Site: One site in particular is known for its abundance of sand dollars. According to this fossil collector, Take Hwy 17 south from San Jose towards Santa Cruz/Scotts Valley. Take Mount Hermon Exit in Scotts Valley. Turn right onto Scotts Valley Drive. Turn right onto Bean Creek Road, and drive a little over a mile until you see a tall, sandy roadcut that is fairly steep. However, it is important that the area is off limits, and you will encounter ‘No Trespassing’ signs.

Works Cited:

RMcWilson, “Fossil Sand Dollar Site in Scotts Valley, California,” (Flickr 2009)

“Scotts Valley Town Center Specific Plan EIR, 4.5 Geology and Soils,” (City of Scotts Valley)  http://www.scottsvalley.org/downloads/town_center/4.5%20Geology%20and%20Soils.pdf

Bolinas Lagoon

Geology: The Bolinas shelf is less than 0.3 degrees tilted, meaning that it is quite flat. The seafloor of the bay area near the lagoon is shallow, and has large bedrock outcroppings from the shore to depths of about 25 m. The sediments date to the Neogene epoch.

Paleontology: Fossil hunters have determined that fossilized sand dollars are fairly common in the area.

Works Cited:

“Geology and geomorphology–Offshore of Bolinas Map Area, California,” (USGS 2015) http://pubs.usgs.gov/ds/781/OffshoreBolinas/metadata/Geology_OffshoreBolinas_metadata.html

Further Reading:

“Recent Marine Sediments of Bolinas Bay, California” (UC Berkeley 1968) http://escholarship.org/uc/item/2kf907bg#page-1

Mazourka Canyon

Geology: Inyo County, containing many elevation extremes, has the highest summit in the continental US (Mt. Whitney), and the lowest area in the Northern Hemisphere (Badwater Basin). The canyon is especially perfect for fossil hunting because it drains the water from a large portion of the Inyo Mountains, causing the water to cut a canyon and expose layers of fossils.

Paleontology: Well preserved Paleozoic invertebrate fossils, some 485 to 415 million years old, can be found in the canyon.

girvanellabonanzakingdolomite1a.jpgBlue Green Algae is commonly found.

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So are horn coral.

 

 

 

Works Cited (Highly Recommended to Find More Information) :

“Paleozoic Era Fossils at Mazourka Canyon, Inyo County, California”, http://inyo2.coffeecup.com/mazourkacanyon/mazourka.html

Scotia Bluffs

Geology of the Area:

The Scotia Bluffs sandstone was deposited around two million years ago during the Pleistocene epoch. The fine to medium grained sediment has a maximum thickness of 640 m. It is part of the Upper Wildcat group and overlies the Rio Dell Formation in Humboldt County. Additionally, the cliffs are about 15 miles from the coast and are at an elevation of 550 feet.

Paleontology of the Area:

Shallow fossil marine life from the Pleistocene epoch can be found in the bluffs, with many of the species still thriving today. According to “Unearthing Evidence of Creatures from Deep Time” by Leslie Scopes Anderson, Giant Pacific Scallop (Petinopecten sp.), Clam (Thrasia sp.), Cockle Shell (Clinocardium meekianum), Sand Dollar (Scutellaster sp.), Moon Snail (Nautica clause), Pandora shell (Pandora sp.), Razor Clam (Siliqua oregonensa) and Shelly sandstone (Psephidia sp.) have been recovered from the area. See image below.

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Works Cited:

Hugh McLean, “Federal Lands Assessment Program: Eel River (Humboldt) Basin, California (Province 80),” (USGS 1988) <http://pubs.usgs.gov/of/1987/0450i/report.pdf&gt;

Leslie Scopes Anderson, “Unearthing Evidence of Creatures from Deep Time,” (Humboldt U 2011) www2.humboldt.edu

Mt. Diablo

**Remember that Mt. Diablo is within a State Park. It would be best to just take pictures of fossils found.

Geology of the Area:

According to the Mt. Diablo Interpretative Association, Mt. Diablo is a mountain with an elevation of 3849 feet in the Diablo range. Although the mountain has only very recently emerged, the rocks it is composed of are very old. Due to its complex geological history, the rocks of Mt. Diablo can be divided into three groups, Mt. Diablo Ophiolite (Jurassic), Franciscan Complex (Jurassic and Cretaceous), and Great Valley Group (Jurassic and Cretaceous). Additionally, the younger sedimentary rocks on the higher strata are Cenozoic.

Mt. Diablo Ophiolite: An ophiolite is a part of oceanic crust and the underlying upper mantle that has been uplifted and exposed above sea level and often developed onto continental crustal rocks. According to radioactive and fossil-age determinations, the ophiolite emerged approximately 165 million years ago. The ophiolite basalt has a crystalline feel with a black to greenish-brown hue. This is created when lava erupts underwater and ‘freezes’ when it makes contact with the water. Diabase is a coarser version of the ophiolite basalt that is created by lava erupting from vertical fissures underwater. Serpentinite can also be found on Mt. Diablo.

The middle area of the Mt. Diablo strata known as the Franciscan Complex is the result of 140 million years of east-dipping subduction. Concerning fossils, approximately 10% of the Franciscan Complex is composed of shale. Unfortunately, most of it has been converted to argillite as a result of metamorphism.

The Great Valley is composed of sedimentary shale and sandstone from the Upper Jurassic to the Cretaceous period. It is mostly deep-water shale. There are also younger Cenozoic strata on top. As a result of the drying of Central Californian basins during the Miocene and Pliocene, marine fossils end at that time.

Paleontology and Fossils:

Cow and Aelurodon jaws have been found, in addition to plants. Marine fossils from both deep and shallow water environments have been recovered.

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This article contains detailed information and directions to a trail that leads to fossils in Mt. Diablo State Park.

Works Cited:

“The Rocks of Mt. Diablo- Their Type and History,” (Mt. Diablo Interpretative Association 2016) www.mdia.org 

 

Sespe Wilderness

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

 

Jalama Beach

Geology of the Area:

The cliffside of this beach contains shale from the Monterey Formation. The fossiliferous shale dates back to the Miocene epoch. There are talus slopes in many areas created by folded and slanted strata. jalama04.jpg

Be careful of falling shale from the cliffside. Although it poses a hazard, the fallen rocks are more convenient to split than extracting shale from the outcropping. Split fishes can be found near the bottoms of the formation. Additionally, petrified whale bone has been recovered on the beach.

 

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As you can see in the figure above, three prominent outcroppings jut out from the Monterey formation, marked 1, 2, and 3 on figures B and C above. Figure A shows that Jalama Beach, to the left of Gaviota, is part of the Monterey Formation bearing marine Miocene fauna, and Oligocene rocks are found more inland.

Paleontology:

Fossil fish and petrified whale bone are in the outcroppings.

Use this Stanford Study of Lompoc Fossil Fishes to identify your fish finds.

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Works Cited:

David Jordan, et.al, “Fossil Fishes of Diatom Beds of Lompoc, California,” (Stanford University, 1920)

Images: “Jalama Beach,” (The Nautiloid Network) www.nautiloid.net 

Kathleen Surpless, et.al, “Evolution and stratigraphic architecture of marine slope gully complexes: Monterey Formation (Miocene), Gaviota Beach, California,” (Trinity University, March 27, 2007)