Antoine Canyon Formation is named for exposures in Antoine Canyon (type locality: sec.13, T15N R12E, Duncan Peak 7.5' quad), Placer Co, CA. Reference localities are found in Manilia Canyon and Screwauger Canyon (sec.18, T15N R13E). Consists of thick-bedded, parallel-laminated, generally fine-grained quartzite with minor thin beds of black pelite. Total thickness is unknown; thickness at type locality is at least 2700 m. Base of unit is not exposed; locally overlain in much of map area by the Screwauger Breccia (new) and the Big Valley Bluff Formation (new). Age is Ordovician(?) to Devonian(?) based on regional stratigraphic relationships.
Source: GNU records (USGS DDS-6; Menlo GNULEX).
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
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