Type locality is here designated as immediately east of Bright Dot Lake, easternmost lake in Convict Creek drainage, [Mount Morrison 15' quad, Mono Co, CA]. Is exposed almost continuously from northernmost exposure in east wall of canyon of Laurel Creek, southeast to termination against granodiorite near Mount Baldwin, distance of 6 mi. Consists of lower massive unit (1000 to 1500 ft thick) which grades upward into well-layered unit (500 to 1000 ft thick). Lower unit consists of microgranular, gray to dark-gray pyritic muscovite, siliceous hornfels, and metachert. Upper unit is sequence of siliceous calc-hornfels and siliceous hornfels in alternate layers (fraction of inch to several ft thick). Maximum exposed thickness at type is about 2000 ft. Underlies Mount Baldwin marble (new). Base not exposed; in fault contact with underlying metasedimentary rocks along entire length. Shown on geologic map of Mount Morrison 15' quad as lowest formation in Bloody Mountain block. Age is Pennsylvanian(?) [probably based on stratigraphic relations]

Source: GNU records (USGS DDS-6; Menlo GNULEX).