- GeoRef, Copyright 2008, American Geological Institute. Reference includes data from Bibliography and Index of North American Geology, U. S. Geological Survey, Reston, VA, United States
Polished pebbles marked with parallel microstriations occur in Miocene rocks in California and various stratigraphic units elsewhere. The striations tend to be oriented normal to the regional structural trend. Tectonic origin of polish and striations by internal movement during deformation is suggested.