Much like the other nearby lakes in the southeast portion of the Point Reyes peninsula , Bass Lake occupies a natural synclinal depression formed behind blocks of rock displaced by landslides within the past 10,000 years . The depressions forming Crystal , Pelican and Bass lakes appear to have been caused by the Double Point Slide , which covers an area of about . The rocks involved in the landslide are shale , chert and sandstone , some similar to Miocene rocks of the Monterey Formation and others to Pliocene rocks from the Central Coast Ranges . The process that caused these slides is ongoing , with several nearby slides caused by the 1906 San Francisco earthquake and others happening as recently as 1956
1906 San Francisco earthquake
1906 San Francisco earthquake
Bass Lake (Marin County, California)