THE 



JOURNAL OF GEOLOGY 



A Semi-Quarterly Magazine of Geology and 

 Related Sciences 



Editors 



T. C. CHAMBERLIN, in General Charge 



R. D. SALISBURY R. A. F. PENROSE, Jr. 

 Geographic Geology Economic Geology 



J. P. IDD1NGS C. R. VAN HISE 



Petrology Pre-Cambrian 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 Yale University 



CHARLES BARROIS C. D. WALCOTT 



Prance U. S. Geological Survey 



ALBRECHT PENCK J. C. BRANNER 



Austria Stanford University 



HANS REUSCH I. C. RUSSELL 



Norway University of Michigan 



GERARD DE GEER W. B. CLARK 



Sweden Johns Hopkins University 



O. A, DERBY 



Brazil 



VOLUME XIII 



CHICAGO 



£1)e Sinibenutg of (STIjicago ^ress 



i9°5 



