zzzzzPg. 148. Mud Springs Mountain formation of El Paso group [author does not capitalize rank terms; however, units are considered formal]. "The BRIDGITES reef above the oolite [Jose formation] is named the Mud Springs Mountain formation, being exceptionally well exposed and developed in Mud Springs Mountain (called Mud Springs Mountains on the map) near Hot Springs, New Mexico. Overlying, largely barren, thin-bedded limestones are named the Snake Hills formation, being exceptionally well exposed in those hills southwest of Deming..." Underlies Snake Hills formation (new) and overlies Jose formation (new). Age is Early Ordovician (middle Canadian; Demingian). Canadian treated as a system in this report. Author states that his philosophy of nomenclature is contrary to "the present fashion of delimiting formations on lithology alone." The resulting proposed divisions of the El Paso Group are thus "a succession of strata and faunas."
Type locality not designated. Named from exposures in Mud Springs Mountain, near Hot Springs, [Sierra Co., NM, in the Orogrande basin].

Source: GNU records (USGS DDS-6; Denver GNULEX); US geologic names lexicon (USGS Bull. 1350, p. 513).