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.

vaughngulchcorals1b

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

Best Guide to Finding Fossils at Scotia Bluffs

Directions:

“Approach the bluffs from an access point on the southeast side of the Rio Dell/Scotia bridge. Walk along the railroad tracks (abandoned) under Highway 101 to the Bluffs. There is no automobile access beyond the parking lot that belongs to Pacific Lumber. Check in with their guard. If you’re lucky, it’s the gentleman who knows more about the local fossils than just about anyone else in Humboldt. Park your car with him or his coworkers.

Be sure to take a knapsack or backpack as this is a hike out to the bluffs. Walk along the tracks until you can see the railroad bridge. This is where the big pelecypod mollusks (look like the Shell Oil insignia) are found in mudstone or eroding out. they can be up to about 9 inches across if complete.

Cross the railroad bridge with caution to an exposure of sandstone or sand. This is the area which produces sand dollars and concretions which contain mollusks and other fossils.” (from Fossil Localities, cited below).

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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Other Fossil Sites Nearby:

Other fossil hunting sites nearby include Centerville Beach and Elk Head.

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

“Fossil Localities”, http://ebeltz.net/fieldtrips/humfossils.html

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.

hash

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

Where to Find Fossils at Sperry Wash

Geology of the Area:

The Sperry Wash in the Alexander Hills near Death Valley contain sediments from the surrounding China Ranch beds. The China Ranch beds are over 5000 feet thick and contain conglomerate Pleistocene lake deposits. The upper beds contain marly limestone and tuffs.

Paleontology:

Although before 1966 the area was considered unfossiliferous in exception to the wood fragments found in the stretch of road described below,  permineralized tree ferns, palm axes, rootlets, and material referred to as petrified bog have been found in the area. Additionally, permineralized grass species such as Tomlinsonia are fossilized in the sediments.

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Directions:

According to Gail Butler’s Rockhounding California, From the interstate 127, turn east on Furnace Creek Road. After driving for 4 miles southeast, stay on Furnace Creek when it branches right away from Old Spanish Trail Road. Turn right on Western Talc Mine Road and drive 2.5 miles to the talc mine. Fossil algae and talc can be found by the mine. Then back out and continue driving for another 4.7 miles farther. Agate and petrified wood can be found on both sides of the road in that stretch of road.

Works Cited:

Tidwell, William D. and Nambudiri, E. M. V., “Tomlinsonia stichkania sp. nov., a permineralized grass from the Pliocene to (?)Pleistocene China Ranch beds in Sperry Wash, California” (1990). All Faculty Publications. Paper 1446. http://scholarsarchive.byu.edu/facpub/1446 

Gail Butler, “Rockhounding California,” (Morris Book Publishing, 1995)