Volume XVI Numbers 



THE 



Journal of Geology 



A Semi=Quarterly flagazine of Geology and 

 Related Sciences 



APRIL-MAY, igo8 



EDITORS 



T. C. CHAMBERLIN, in General Charge 



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



Geographic Geology Economic Geology 



J. P. IDDINGS C. R. VAN RISE 



Petrology Structural Geology 



STUART WELLER W. H. HOLMES 



Paleontologic Geology Anthroptc Geology 



S. W: WILLISTON, Vertebrate Paleontology 



ASSOCIATE EDITORS 



SIR ARCHIBALD GEIKIE G. K. GILBERT 



Great Britain Washington, D. C. 



H. ROSENBUSCH H. S. WILLIAMS 



f Germany Cornell University 



CHARLES BARROIS C. D. WALCOTT 



France Smithsonian Institution 



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 



Ete mnibersitg ot ari)icago ^^ress 



CHICAGO AND NEW YORK 

 William Wesley & Son, London 



