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 (Citation 1), “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

 

Advertisements

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