GMAT Critical Reasoning (CR) | Re: Verbal Focus Q: Layers of the earth’s crust are exposed

Layers of the earth’s crust are exposed at several points along California’s San Andreas Fault. Notably, a team of geologists recently spotted a remote fold of exposed crust along the fault that contained shells of a species of mollusk from 500,000 years agothat can only survive at least 500 feet below the surface of the ocean . The exposed crust is comprised of the same sediment consistent with the known habitat of the mollusk. Surprisingly, however, ocean levels have generally been lower
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