The late Paleozoic sediments of the Gore area in Eagle and Summit counties, Colorado, are described as to lithology, thickness, stratigraphic relations, geologic history, and fauna. The stratigraphic names Weber and Maroon are abandoned in the area and in their place the name Battle Mountain formation is proposed (FOOTNOTE 3) for the thick sequence of Pennsylvanian clastics. The term Belden shale member of the Battle Mountain formation is proposed to replace the name Weber shale in the area. The Robinson and Jacque Mountain limestones are reduced to the rank of members of the Battle Mountain unit. The manuscript name of State Bridge formation is here applied to the upper Pennsylvanian or Permian sediments which lie between the Battle Mountain formation and the Triassic. >

The erstwhile Permian plant Walchia is found to be associated with marine invertebrate fossils of Des Moines age. At least a part of the gypsum of the Eagle Basin is shown to be of Des Moines age.