Mesaverde group is substituted for Mesaverde formation throughout the San Juan basin, and the formations of the type locality, the Point Lookout sandstone, Menefee formation, and Cliff House sandstone, are also extended throughout the basin. Several names for units formerly called members of the Mesaverde formation in the southern part of the basin are retained as names of tongues or members of the formations of the Mesaverde group. The name Gallup sandstone replaces the name Tocito sandstone lentil of the Mancos shale. Crevasse Canyon formation of Allen and Balk (1954) is accepted for that part of the Mesaverde group between the Gallup and Point Lookout sandstones, with the Gibson coal member (restricted) at its top. A new name, the Cleary coal member of the Menefee form tion, is proposed for the beds formerly included in the upper part of the Gibson coal member of the Mesaverde formation.