1. Middle and Lower Ordovician formations in southernmost Nevada and adjacent California Author/Creator: Ross, Reuben James, 1918- Publication/Creation: Washington [D.C.] : U.S. G.P.O., 1964 Resource Type: Book Access & Availability: Loading
2. Middle and Upper Ordovician nautiloid cephalopods of the Cincinnati arch region of Kentucky, Indiana, and Ohio Author/Creator: Frey, Robert C. Publication/Creation: Denver, CO : For sale by U.S. Geological Survey, Information Services Resource Type: Book Access & Availability: Loading
3. Middle and Upper Ordovician symmetrical univalved mollusks (Monoplacophora and Bellerophontina) of the Cincinnati arch region Author/Creator: Wahlman, G. P. (Gregory Paul) Publication/Creation: Washington : U.S. G.P.O., 1992 Resource Type: Book Access & Availability: Loading
4. Middle Ordovician carbonate shelf to deep-water basin deposition in the southern Appalachians Publication/Creation: Knoxville : University of Tennessee, Dept. of Geological Sciences, 1980 Resource Type: Book Access & Availability: Loading
5. A monograph of the British Ordovician and Silurian Bellerophontacea Author/Creator: Reed, F. R. C. 1869- (Frederick Richard Cowper) Publication/Creation: London : Palaeontographical society, 1920-21. Resource Type: Book Access & Availability: Loading