peat - silty peat from the San Andreas fault zone, formed in a marsh that dried out roughly a century ago - large display specimen with the black looking just

with the black looking just like weathered obsidian

When both sides are shown

garnetiferous sand from Pfeiffer Beach

such as the orange red sand derived from the Navajo Sandstone

sometimes with the central opening collapsed

peat - silty peat from the San Andreas fault zone, formed in a marsh that dried out roughly a century ago - large display specimen with the black looking justThis silty peat was collected from a former marsh along Pallett Creek in the San Andreas fault zone, Los Angeles County, California Peat is formed by partial decomposition of plant material under acidic conditions. With burial and compression, peat forms lignite and eventually bituminous coal. At Pallett Creek, the peat was formed in a marshy sag pond in the fault zone. Layers of leaves and vegetation fell into the marsh and were subsequently covered