The Rocks of San Francisco Bay

Hazards to navigation on San Francisco Bay include major submerged rocks, most of which were topped off in dramatic explosions in the early 20th century. The US Geological Survey has a comprehensive publication that discusses the topography under the  bay’s waters, including Shag, Harding, Arch and Blossom Rocks.
https://pubs.usgs.gov/circ/2004/c1259/c1259_tagged.pdf