Beach Balls

July 25, 2005

Bowling_ball_beach copy

Provided and copyright by: Janet Beegle
Summary authors & editors: Janet Beegle; Jim Foster

The photo above showing beach ball size concretions was taken on the beach in Gualala, California in October 2004. These concretions likely formed around a fragment of shale or sandstone, then became encased in the cliff in the background, before gradually eroding out and rolling down toward the shore. Concretions, while certainly curious, are hardly rare. They can be found in all types of sedimentary rock. See also the Earth Science Picture of the Day for May 5, 2005.

Related Links: