PROCEEDINGS 



OF THE 



CALIFORNIA ACADEMY OF SCIENCES 



Fourth Series 



Vol. XI, No. 1, pp. 1-26 July 6, 1921 



Notes on a Fauna of the Vigo Group and 



Its Bearing on the Evolution of 



Marine Molluscan Faunas 



BY 



Roy E. Dickerson 



Honorary Curator, Department of Invertebrate Paleontology 



SAN FRANCISCO 



Published by the Academy 



1921 



