[7][8] The depressions forming Crystal, Pelican and Bass lakes appear to have been caused by the Double Point Slide, which covers an area of about 1.7 square miles (4.4 km2).

In this coastal zone there are open stands of coyote brush (Baccharis pilularis), often with native grasses such as California oatgrass (Danthonia californica) and purple needlegrass (Nassella pulchra).

[2] Research in 1976 found that the lake supported a range of phytoplankton from the genera Anabaena, Cryptomonas, Cymbella, Fragilaria, Oocystis, Schroederia, Sphaerocystis and Staurastrum, as well as the species Ceratium hirundinella, Elakatothrix gelatinosa and Pseudokephrion conicum.

[12][13] Bass Lake is inland from the 86-acre (35 ha) Double Point Area of Special Biological Significance, established in 1974 primarily to protect the large population of harbor seals (Phoca vitulina) that raise pups on the beach between April and June each year.

[16] Prior to geological research in the 1960s that revealed the many pre-historic landslides, the area was considered to be sufficiently stable for the U.S. Army to construct an underground artillery control facility within the North Point headland directly west of Pelican Lake in 1944.