Seal Rock is a large and prominent rock found at the North end of the Ocean Beach in San Francisco. Ocean Beach is a beach that runs along the west coast of San Francisco, California at the Pacific Ocean. ... This page is a candidate for speedy deletion. ...

Ocean Beach on a cold day

Image File history File links Took this myself This work is copyrighted. ... Image File history File links Took this myself This work is copyrighted. ...

The geology and history of the area

Near the end of the last ice-age, this part of the coastline was thought to be between eight and twenty five miles further westward of its current position - around five thousand years ago, with the melting of the ice, the sea level rose to its current level.

The coastal features found here today were formed by the actions of waves and the wind and sand movement. The geology of this part of of the coastline of San Francisco consists of steep rocky cliffs which are punctuated by narrow sandy pocket beaches found at the north end of the city and long sandy stretches at Ocean Beach and Fort Funston to the south.

The local features and indeed the entire peninsula come from the northern aspect of the Santa Cruz mountain range. Before the urban development seen today the area landward of Ocean Beach consisted of barren sand fields inland to Twin Peaks. The first known map of the area, dating from 1852 and was made by the United States Coastal Survey and it describes the coastline here as being entirely unaltered by humans. Santa Cruz, Spanish and Portuguese for Holy Cross, is the name of several cities, regions, and other geographical features around the world: Argentina Puerto Santa Cruz, Santa Cruz province Santa Cruz Province, Argentina Bolivia Santa Cruz de la Sierra Santa Cruz Department Brazil Santa Cruz, Espírito Santo Santa Cruz... Ocean Beach is a beach that runs along the west coast of San Francisco, California at the Pacific Ocean. ...

The geologic layers beneath Ocean Beach, starting from the top (i.e. the youngest) are:

• Placed fill. The placed fill comes from various construction activities that have taken place over the last 100 years or so.The depth of this placed fill varies, but in 1985 it was then estimated to be between 7-16 feet.
• Dune sands. The layer of dune sand has been estimated to be between 13-26 feet deep.
• Colma Formation
• Merced Formation
• Bedrock. The depth to bedrock is estimated to be between 350-400 feet.

The Colma and Merced Formations consist generally of poorly sorted sandy deposits and were probably deposited during some earlier period of greater sea levels. The Colma Formation is found under the dune sands and also extends inland. Mesquite Flat Dunes in Death Valley National Park In physical geography, a dune is a hill of sand built by eolian (wind-related) processes. ... Colma is a small town in San Mateo County, California, at the northern end of the San Francisco Peninsula next to Daly City and South San Francisco. ... Merced can refer to: The town of Merced, California The Merced River in California Merced County, California The Itanium Merced processor This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... Bedrock is the native consolidated rock underlying the Earths surface. ...

External Links

• San Francisco Dept of Environment link
• Link to a commercial picture of the rock