Thirty mollusks are known definitely from the Pleistocene Bay Point formation at its type locality at Crown Point, San Diego County, California. The pelecypod Donax gouldi is the most abundant, and in places the rock is a Donax coquina. The formation as a whole is an open sandy beach deposit. The presence of Rissoina nereina and the echinoid Mellita longifissa indicates that sea-water temperatures were warmer than now.