V 





THE 



JOURNAL OF GEOLOG\ 



A Semi-Quarterly Magazine of Geology and 

 Related Sciences 



/ 



Editors 



T. C. ClIA.MliKRLIX 

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



Geographic Geology Economic Geology 



J. 1'. IDDINGS C. R. VAN RISE 



Petrology '■. Pre-Camhrian Geology 



W. H. HOLMES, Anthropic Geology 



Associate Editors 



SIR ARCHIBALD GEIKIE 



Great Brifai 77 

 H. ROSENBUSCH 



Germa7iy 

 CHARLES BARROIS 



France 

 ALBRECHT PENCK 



Austria 

 HANS REUSCH 



N' or way 

 GERARD DE GEER 



Sweden 

 GEORGE M. DAWSON 



Canada 



O. A. DERBY, Brazil 



JOSEPH LE CONTE 



University of Calijoriiia 

 C. D. WALCOTT 



U. S. Geological Suri'ey 

 G. K. GILBERT 



Washington, D. C. 

 H. S. WILLIAMS 



Vale University 

 j. C. BRANNER 



Lelafid Stanford University 

 I. C. RUSSELL 



University of Michigan 

 WILLIAM B. CLARK 



fohns Hopkins Unii'ersity 



VOLUME V 



CHICACiO 



C1)c sauiberisitp of iSTiiicago IJress 



iSg; 



