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Rock Formations
Middle TN - Bigby Cannon

Field Guide to outcrops include:


The Bigby-Cannon Formation is part of the Nashville Group and is dated to the late Ordovician Period.

Composed of 3 facies: (1) the Bigby facies is blue gray, massive, granular, crossbeded and phosphatic. (2) Dove faces is a light gray (Dove colored) dense fine-grained limestone. (3) Cannon facies is blue grey limestone, massive but non-phosphatic. All facies weather to reddish-brown clay usually less than 10 feet thick. Some sinkhole development and considerable deep weathering along vertical fractures. Outcrops in Central Basin. Mines for phosphate in several counties of Central Basin.

- H.R. Beaver,
geological engineer