Along the coastline of Southern California, the look of the beaches is reflective of the ancient history of the area. Some beaches contain sand that originated in the San Gabriel Mountains. "Sediment that's derived from granite type watersheds is generally comprised of a lot of quartz," said Tony Orme, a UCLA geography professor. "It tends to be light in color." In other areas, beaches contain sand with red and black flecks -- telltale signs of ancient volcanic activity.

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