Fossils Found at Half Moon Bay

Paleontology:

Scallop imprint found on beach:

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Other Fossil Sites Nearby:

Bolinas Lagoon: link

Mt. Diablo: link

Pleasanton Sunol Road: link

Ultimate Guide to Finding Fossils at Point Loma

Geology:

Point Loma is part of the Point Loma Formation, near the coastline of San Diego. According to the second citation, “The massive, ungraded sandstones in the Point Loma Formation have sharp upper and lower contacts, thick lenses of mudstone clasts, and common load-deformation structures, suggesting deposition largely by grain-flow processes.”

Paleontology:

The Upper Cretaceous strata in the Point Loma formation contain abundant trace fossils of the species Qphiomorpha and Thalassinoides, which suggest that the area was a shallow sea during the Cretaceous Period.

Directions:

According to The Fossil Forum, “Towards San Diego, get off at the Tecolate Road/Sea World exit. Proceed west on Sea World Drive — past Sea World, it becomes Sunset Cliffs Blvd. Drive to the end of Sunset Cliffs and park in the lot for Sunset Cliffs Park. Look along the top of the sea cliff.”

Works Cited:

Gary Kindel, “Fossil Collecting Sites in North America,” (Digital Rockhound’s Companion Site 2009) http://www.digitalrockhound.blogspot.com

Philip Kern et al, “Trace Fossils and Bathymetry of the Upper Cretaceous Point Loma Formation, San Diego, California,” (San Diego State U, Rice U 1974) http://gsabulletin.gsapubs.org/content/85/6/893.abstract

Where to Find Fossils at Coal Point, Isla Vista

Geology: The fossiliferous layers are part of an unnamed Pleistocene formation. Once you park, walk down to the beach and look for the sedimentary rocks on the beach cliff. However, the geology of the area should be similar to the Monterey formation which contains both Gaviota Beach, and Jalama Beach.

Fossils: The layers of sandstone contain marine assemblages from the Pleistocene epoch.

Other Fossil Sites Nearby:

Rincon Point: link

Ojai Trails: link

Sespe Wilderness: link

Surfer’s Knoll: link

Where to Find Fossils in Jack’s Peak County Park

Geology: According to the USGS, “Geophysical data and sea floor samples collected from the continental shelf and slope between Ano Nuevo Point and Point Sur, California indicate that the Monterey Bay region has had a complex late Cenozoic tectonic history“, meaning that it is difficult to easily date the fossils based on location. See the Further Reading to learn more about the geology of the Monterey Bay region.

Fossils: Fossils containing small leaves and shells are in shale a hundred yards down the trail from the west parking lot.

Further Reading/Works Cited:

Gary Greene, “Geology of the Monterey Bay region, California” (USGS 1977) https://pubs.er.usgs.gov/publication/ofr77718

Ultimate Guide to Finding Fossils in 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

Where to Find Fossils at 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.

Other Fossil Sites Nearby:

Pleasanton Sunol Road: link

Half Moon Bay: link

Mt. Diablo: link

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

Finding Fossils in 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

Observing Fossils Found at the La Brea Tar Pits

Background:

The pits are composed of heavy oil fractions called gilsonite, which emerged from the Earth as oil. These deposits had become topped with water, dust, and leaves. Animals would venture in and become trapped, luring predators who come to eat the animals and become trapped themselves. The thick tar then encases the bones, preserving them remarkably well.IMG_4872.JPG

Paleontology:

The preserved organisms in it are mainly from the Pleistocene epoch, although a great deal of finds date from prehistory (10 kya — 4 kya). Saber-toothed cats, mastodons, ground sloths, bison, western horse, and camelids are . Dire wolves are the most common large land mammal found there.

The La Brea Tar Pits Museum has made a beautiful timeline of the creatures found in the tar pits here.

Learn More about the Tar Pits and the Museum here, and watch Will Ferrell speak sabertooth.

Ultimate Guide to Finding Fossils at Mt. Diablo

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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Directions to Finding Fossils at Mt. Diablo:

Driving Directions:  “In Walnut Creek on Interstate 680, take Ygnacio Valley Road east to Oak Grove Road. Turn right (south) and continue as this road becomes Castle Rock Road. Proceed to the end of the road where it is blocked by a gate and there is parking on the left. Access is free.” (Geohiking.com)

Once you arrive:

“From the parking area, you will notice the equestrian and cyclist trailhead across the road. The hikers’ route is past the gate on the paved road into Castle Rock Park. You can take either. Walk up the paved road into the park past the picnic area, swimming pool, and park buildings. This is a private park, but hikers are allowed trail access through it. The road turns to gravel past the restrooms. You will be walking through Pine Canyon alongside Pine Creek all the way with moderate shade. The trail is an old wagon road called Stage Road (and signed that way as well).

Leaving Castle Rock Park behind, you will pass a gate and continue to a fork. Bear right to stay on Stage Road. Before long you arrive at a sandstone wall on the right.

A short distance further you arrive at a rock on the right with a hole bored through it by water erosion. You won’t be the first person to climb up into the round room inside the rock.

There are many creek crossings on this trail, seven of them, and it may not be much fun from December to March, depending on rainfall and horse traffic.

After the first stream crossing, you will spot a narrow footpath leading to the right through the grass. In spring when the grass is growing, this path may not be apparent. If you come to the second creek crossing, you missed it, but by turning right and following the edge of the creek a short distance, you will be there. Take the footpath past a grape arbor of sorts to a slide in a tall cliff above the creekbed. There is a rich layer of marine fossils in this cliff. Some of these wash down to the creekbed each year. If you look carefully for whitish rocks, you will find pieces of this exposure. Thick clusterings of mollusk shell fragments can be seen. This sort of rock, composed mainly of shells with some sandstone is known as a “hash” for somewhat obvious reasons. Shell hashes in the Diablo foothills are generally of the Briones Formation. You can see these on Rocky Ridge in Las Trampas Regional Park, Fossil Ridge on Mt. Diablo, and various other locations in the area. If you look closely at the shell pieces, you may find some that are large enough to recognize as a clam, the dominant type of fossil. Pectens, the bivalve mollusk made famous as the symbol for Shell Oil Company, also occur, but are less common.” (Geohiking.com)

Other Fossil Sites Nearby:

Other fossil hunting sites nearby include Bolinas LagoonPleasanton Sunol Road, and Half Moon Bay.

Disclaimer: California Fossils focuses on hosting a user-friendly interface and a flexible platform where your finds can be published almost instantly. However, we realize that increased traffic to fossil sites leads to erosion and degradation of sites, which is why we strongly recommend not removing fossils and leaving them where they have been found for others.

Works Cited:

“Castle Rock”, Geohiking.com, http://geohiking.com/castlerock.html

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

Guide to Finding Fossils in the 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.

Other Fossil Sites Nearby:

Coal Point: link

Rincon Point: link

Ojai Trails: link

Surfer’s Knoll: link

Works Cited:

MCKAY, HANNAH. QUATERNARY STRATIGRAPHY AND GEOLOGIC EVOLUTION OF OJAI AND UPPER OJAI VALLEYS, WESTERN TRANSVERSE RANGES, CALIFORNIA. P.2011