Start at the southern end of the Coastal South Trail and head east. The trail starts out dropping on a fairly straight trail. Soon, the very tight switchbacks will start and continue, and proceed until you are dropped out in a flat field.
During the Civil War, the U.S. Army hastily built two batteries, armed with 10-inch Rodman guns, at a site that locals called Black Point. These armaments at Point San Jose Military Reservation (later called Fort Mason) served as backup to the fortifications on Alcatraz and at Fort Point.
