It preserves fossils dating back to the early Silurian period.

It has a light and dark banded appearance due to alternating beds of light gray peritidal laminated carbonate mudstone and dark gray cherty wackestone or packstone containing abundant corals.

[4] The upper contact shows that the area was tilted and eroded prior to the Devonian.

[3] The formation is divided into the Chamberino, Flag Hill, and Crazycat members in the Sacramento Mountains.

These include the corals Cyanthophyllum, Favosites, Halysites, and Heliolites and the gastropod Hormatoma.