The Fournal of Geology 
Published on or about the following dates: February 1, March 15, May 1, June 15, 
August 1, September 15, November 1, December 15. 
Vol. XX CONTENTS FOR FEBRUARY-MARCH, 1912 No. 2 
AN EXPERIMENTAL CONTRIBUTION TO THE QUESTION OF THE DEPTH OF THE ZONE OF FLOW 
IN THE EARTH’S CRUST She eed ee em nee Mr REC TT te mt ee ele St DEANE ADC ADAMS EN GT 
ON THE LIMITING STRENGTH OF ROCKS UNDER CONDITIONS OF STRESS EXISTING IN THE 
ARTES aINSD PE RORY ace ngewe tae ee em eee eke eee ae ee ae OUTS VE SSO GING 119 
AN OLD EROSION SURFACE IN IDAHO: ITS AGE AND VALUE AS A DATUM PLANE 
: JosrrH B. UmPLEBY 139 
BUGENSHUSSA Kise re te i rare ee nO re eee eo ene ete eg eee Micurt A. Lispoa 148. 
THE PETROGRAPHIC CHARACTER OF OHIO SANDS WITH RELATION TO THEIR ORIGIN 
D. Date ConpDIt 152 
SOME OBSERVATIONS AND EXPERIMENTS ON JOINT PLANES - - - = =  - Peart SHELDON 164 
REVIEWS ee ee ee ee Ce et eee eg en ache ie eae ee te a eee ee 
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