MEMBERS OP THE UNIVERSITY GEOLOGICAL SURVEY 



FBANCIS H. SNOW, 

 Chancellor, and ex officio Director. 



SAMUEL W. WILLISTON, 



Department of Historical Geology and Paleontology. 



ERASMUS HA WORTH, 

 Department of Physical Geology and Mineralogy. 



EDGAR H. S. BAILEY, 

 Department of Chemistry. 



FOR VOLUME IV. 



SAMUEL W. WILLISTON, Paleontologist. 

 GEORGE I. ADAMS, Assistant Paleontologist. 

 ERMINIE C. CASE, Assistant Paleontologist. 

 CLARENCE E. McCLUNG, Assistant Paleontologist. 

 WILLIAM N. LOGAN, Assistant Paleontologist. 



