San francisco dating and dumping guide
About 560,000 years ago, a tectonic shift caused the large inland Lake Corcoran to spill out the central valley and through the Carquinez Strait, carving out sediment and forming canyons in what is now the northern part of the San Francisco Bay and Golden Gate strait.Until the last ice age, the basin which is now filled by the San Francisco Bay was a large linear valley with small hills, similar to most of the valleys of the Coast Ranges.Isolated in the center of the Bay is Alcatraz, the site of the famous federal penitentiary.The federal prison on Alcatraz Island no longer functions, but the complex is a popular tourist site.
The bay was designated a Ramsar Wetland of International Importance on February 2, 2012. Later, wetlands and inlets were deliberately filled in, reducing the Bay's size since the mid-19th century by as much as one third.Attached to the north is the artificial and flat Treasure Island, site of the 1939 Golden Gate International Exposition.From the Second World War until the 1990s, both islands served as military bases and are now being redeveloped.It enters the bay at Alviso, a neighborhood of San Jose.
It then connects to the Pacific Ocean via the Golden Gate strait.San Francisco Bay drains water from approximately 40 percent of California.