1. Cambrian and Ordovician rocks of southern Arizona and New Mexico and westernmost Texas Author/Creator: Hayes, Philip T. 1923- (Philip Thayer), author Publication/Creation: Washington : United States Department of the Interior, Geological Survey, 1975 Resource Type: Book Access & Availability: Loading
2. Cambrian and Ordovician rocks of southern Arizona and New Mexico and westernmost Texas Author/Creator: Hayes, Philip T. 1923- (Philip Thayer) Publication/Creation: Washington : U.S. Govt. Print. Off, 1975 Resource Type: Book Is Part Of: U.S. Geological Survey professional paper, no.871-879. Access & Availability: Loading
3. The Cambrian-Ordovician boundary : sections, fossil dis-tributions and correlations Author/Creator: Bassett, Michael G. Publication/Creation: Cardiff, Wales : National Museum of Wales, 1982 Resource Type: Book Access & Availability: Loading
4. Carbonate rocks of Cambrian and Ordovician age in the Lancaster quadrangle, Pennsylvania Author/Creator: Meisler, Harold Publication/Creation: [Washington] : [U.S. Govt. Print. Off], [1968] Resource Type: Book Is Part Of: U.S. Geological Survey bulletin, no.1253-1256. Access & Availability: Loading
5. Carbonate rocks of Cambrian and Ordovician age in the Lancaster quadrangle, Pennsylvania Author/Creator: Meisler, Harold, author Publication/Creation: [Washington, D.C.] : United States Department of the Interior, Geological Survey, 1968 Resource Type: Book Access & Availability: Loading
6. The Chopawamsic Formation-- : a new stratigraphic unit in the Piedmont of northeastern Virginia Author/Creator: Southwick, D. L. 1936- (David Leroy), author Publication/Creation: [Washington, D.C.] : United States Department of the Interior, Geological Survey, 1971 Resource Type: Book Access & Availability: Loading
7. The Chopawamsic Formation-- : a new stratigraphic unit in the Piedmont of northeastern Virginia Author/Creator: Southwick, D. L. 1936- (David Leroy) Publication/Creation: [Washington] : [U.S. Govt. Print. Off], [1971] Resource Type: Book Access & Availability: Loading