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limestone - teaching hand specimen of a dark gray Lower Paleozoic limestone from the Darwin Hills, Calif.

$ 7.50

The Keeler Canyon Formation is Lower Permian to Lower Pennsylvanian in age. In the Darwin Hills and Talc City Hills it is 500 meters thick. In some areas it has abundant fusilinids. 

Limestones are bioclastic, meaning they are composed of the tiny calcareous exoskeletons of plankton, which rain continuously to the sea floor. These accumulate as calcareous ooze that lithifies with time and compaction to become limestone. This particular limestone is characterized by turbidity flow structures and was deposited as sediment flows down the continental slope.

Limestone varies in color from white, through shades of tan to gray, to black. The weathered surface is usually a lighter shade of gray. The specimen with two coins has some of the weathered gray surface left on one side for comparison.

Select a specimen: You can select a specimen by telling us what is in the photo with it, a black mechanical pencil or pencil plus some number of coins, or you can let us make the selection.

These specimens ship in a small flat rate box unless combined with other purchases. 

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