They consist of interlayered sedimentary and volcanic flow rocks metamorphosed to low greenschist facies. These rocks are frequently metamorphosed greenschist, amphibolite, and granulite facies. The facies are named after the metamorphic rock formed under those facies conditions from basalt. Most fossils are from the siltstone facies. Some show granulite facies metamorphism, but most are the slightly lower temperature amphibolite facies. It consists of a bryozoan facies and an oolitic facies and represents a subtidal shoal. They are classified by texture and by chemical and mineral assemblage (metamorphic facies). It is an indicator mineral of the prehnite-pumpellyite metamorphic facies. The descriptions of strata based on physical appearance define facies. Affected fetuses develop pulmonary hypoplasia, limb deformities, and characteristic facies. This is overlain in western areas by the channel-deposit facies Moss Back Member. The dominant mineral in the carbonate facies is siderite. The dominant mineral in the sulfide facies is pyrite. The Sonsela Sandstone is a braided-stream channel facies. The dominant minerals in the oxide facies are magnetite and hematite.