Cambrian stratigraphy and paleontology near caborca, northwestern sonora, México
Cambrian stratigraphy and paleontology near caborca, northwestern sonora, México - Washington, D. C : Smithsonian Institution, 1952. - vi, 184 p. : láms. ; 21 cm.
Smithsonian Miscellaneous Collections, vol. 119, Nº 1. Charles D. And Mary Vaux Walcott Research Fund