This page updated July 11, 2017.  COMING:  Cape Sebastian, OR, differential weathering.

Rainbow Rock, Brookings, Oregon
Tightly-folded, thin-bedded, polychromatic, deep-water cherts, Dothan Formation

Requa Overlook, Del Norte Co., CA
Monochromatic chert cut by quartz veins, Broken Formation

North Bank, Chetco River, Brookings, Oregon
Northwest-dipping, intensely fractured, metasedimentary rocks, Dothan Formation

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Trinidad, CA, Coastline South of Patricks Point
Bowling Ball Concretions weathering out from a medium-grained Franciscan Formation Sandstone

Tumbled Chert from Beaches Near Brookings, Oregon