A photo of Alcatraz Island
By Geology and Ecology of National Parks
June 2011 (approx.)
Detailed Description
Alcatraz Island, "The Rock", is now part of Golden Gate National Recreation Area. View from from Crissy Field, Presidio. Alcatraz is an island composed of Franciscan sandstone and shale of Cretaceous age (Elder, 1998). Alcatraz was the home of the famous maximum-security prison which is now open for tours.
Sources/Usage
A photo of Alcatraz Island