Named as the lower member of the Percha shale for the Ready Pay Gulch which drains into Percha Creek 400 yds east of The Box in SW1/4 SW1/4 SE1/4 sec 14, T16S, R7W, Sierra Co, NM in the Orogrande basin. Name used in the report area in the Sacramento Mountains on the east to the Mimbres region in the west. No type locality designated. Composed of black to gray, nonfossiliferous shale 132 ft thick at type section of Percha. Has occasional green shale lenses. Is argillaceous in upper part. Unconformably overlies the Silurian Fusselman limestone; contact is a black shale (Ready Pay) on brown siliceous limestone (Fusselman). A thin brown nonfossiliferous siltstone bed was found at the base of the Ready Pay at three scattered localities in the Mimbres region. The thin siltstone is similar to a zone in the Sly Gap. Underlies the Box member (new) of the Percha shale; contact is a gray shale (Ready Pay) under a gray argillaceous limestone (Box); upper contact considered to be gradational. Thought to occur throughout southern NM and probably in the Franklin Mountains. Columnar section. Cross section. Correlation chart. Of Late Devonian age.

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

Is basal member of Percha Shale (Upper Devonian) in central Peloncillo Mountains, Hidalgo Co, NM in Pedregosa basin. Unconformably overlies El Paso Limestone (Lower Ordovician). Underlies Box Member of Percha Shale. Age is Late Devonian; [apparently on basis of previous work].

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

Is the basal member of Percha Formation. Unconformably overlies Silurian Fusselman Dolomite. Grades upward into calcareous nodular shale and limestone of Box Member of Percha. Fossils rare. Has conodonts and 3 species of brachiopods. Conodonts from basal sandy and silty beds indicate member is no older than early Famennian. Is probably the black facies of the Thoroughgood and Rhodes Canyon Formations of the San Andres Area. Record deposition in a deep basin. Present Hillsboro, Sierra Co. (Orogrande basin) and Silver City, Grant Co. (Basin-and-Range province) areas, NM. Correlation charts. Cross sections.

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