Vals, 
Moti NAL OF GEOLOGY 
A Semi-Quarterly Magazine of Geology and 
Related Sciences 
EDITORS 
T. C. CHAMBERLIN, zz General Charge 
R. D. SALISBURY R.A] ES PENROSE, JR. 
Geographic Geology Economic Geology 
J. P. IDDINGS ¢, R. VAN HISE 
Petrology Structural Geology 
STUART WELLER W. H. HOLMES 
Paleontologic Geology Anthropic Geology 
S. W. WILLISTON, Vertebrate Paleontology 
ASSOCIATE EDITORS 
SIR ARCHIBALD GEIKIE G. K, GILBERT 
Great Britain Washington, D. C. 
H. ROSENBUSCH H. S. WILLIAMS 
Germany ; Cornell University 
CHARLES BARROIS Cy Da WALCOTT 
France U.S. Geological Survey 
ALBRECHT PENCK J. C. BRANNER 
Germany Stanford University 
HANS REUSCH W. B. CLARK 
. Norway Johns Hopkins University 
GERARD DE GEER O. A. DERBY 
Sweden Brazil 
T. W. E. DAVID 
Australia 
LEE TR 
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WOEIIIM OES 20 
CHICAGO 
Che Anibersity of Chicago Press 
1907 
