~ Volume XVI. Number 4 
THE 
=e of Geology 
"ie : A Seni = Oliarterly Magazine of Geology and 
Related Sciences 
MAY-FUNE, 1909 
EDITORS 
: T. C. CHAMBERLIN, 7 General Charge 
R. D: SALISBURY R. A. F, PENROSE 
. Geographic Geology Economic Geology 
J. -P. IDDINGS : nC, Re VANIEISE 
: Petrology Structural Geology 
a STUART WELLER W. H. HOLMES 
Paleontologic Geology Anthropic Geology 
S. W. WILLISTON, Vertebrate Paleontology 
“m 
ASSOCIATE EDITORS 
SIR. ARCHIBALD GEIKIE . G. K. GILBERT 
; Great Britain Washington, yO KR OF 
H. ROSENBUSCH H. S. WILLIAMS 
Py Germany ~ Cornell University 
CHARLES BARROIS “ C. D. WALCOTT 
France brite Smithsonian Institution 
ALBRECHT PENCK J. C. BRANNER 
Germany Stanford University 
HANS REUSCH / W. B. CLARK 
Norway Johns Hopkins University ° 
Se DE GEER i” O. A. DERBY 
Sweden . Brazil 
Bien Wer Biz DAVID ie WILLIAM H. HOBBS. 
Australia a University of Michigan 
noe QA nibersity -of- nen Bross: 
CHICAGO AND NEW. YORK 
WILLiam WESLEY & Son, Lonpon 
