Age of first marine terrace near Santa Cruz, California

Five species of shallow neritic Pleistocene mollusks from a central California marine terrace give these Th²³⁰/U²³⁸ ages: 88,000; 68,000; 76,000; 16,000; 100,000; 91,000 (from data in Blanchard and others, 1967). With one exception, the ages fall between 68,000 and 100,000 years. This broad grouping of ages, its general agreement with dates from elsewhere, and geologic evidence suggest that the sea was relatively high in central California sometime during this interval.