dig iia 
POURRA OF GEOLOGY 
A Semi-Quarterly Magazine of Geology and 
Related Sciences 
EDITORS 
T. C. CHAMBERLIN 
R. D. SALISBURY RAS Hee NROSEAMiRe 
Geographic Geology Liconomic Geology 
J. P. IDDINGS C. R. VAN HISE 
Petrology Pre-Cambrian Geology 
W. H. HOLMES, Anxthropic Geology 
ASSOCIATE EDITORS 
SIR ARCHIBALD GEIKIE JOSEPH LE CONTE 
Great Britain University of Calitornia 
H. ROSENBUSCH Cc. D. WALCOTT 
Germany U.S. Geological Survey 
CHARLES BARROIS G. K. GILBERT 
France Washington, D. C. 
ALBRECHT PENCK H. S. WILLIAMS 
Austria Vale University 
HANS REUSCH J. C. BRANNER 
Norway Leland Stanford University 
GERARD DE GEER I, (CG, IRUWSSISILIL, 
Sweden University of Michigan. 
GEORGE M. DAWSON WILLIAM B. CLARK 
Canada Johns Hopkins University 
O. A. DERBY, Brazil 
VOLUME any. 
CHICAGO 
Che BAnibversity of Chicago Press 
1896 
