The Fournal of Geology - — 
Vol. XXI CONTENTS FOR APRIL-MAY 1913 No. 3 
CHEMICAL COMPOSITION AS A CRITERION IN IDENTIFYING METAMORPHOSED SEDIMENTS 
Epson S. Bastin 195. ig 
OBSERVATIONS ON THE FELDSPARS - = - ~ - 9-285. = = |) -')°2° 0 Ausmy Fo) Roceusm 202 
ROCK CLASSIFICATION ON THREE CO-ORDINATES - - - - -  - ALEXANDER N. WINCHELE 208 
THE OLD EROSION SURFACE IN IDAHO - ye - - - - - - -  JoserH B. UmPLesy 
NOTES ON THE ORIGIN OF CERTAIN PALEOZOIC SEDIMENTS, ILLUSTRATED BY THE CAMBRIAN __ 
AND ORDOVICIAN ROCKS OF CENTER COUNTY, PENNSYLVANIA - -  Txomas C. Brown : 
THE SECONDARY PRECIPITATION OF GOLD IN ORE BODIES- - - - -  Atsert D. Brokaw 5 | 
ORIGINAL STREAMS; AND THEIR ROLE IN GENERAL DESERT-LEVELING -  Cuarzes R. Keyes 268 
THE. NATURE OF THE LATER DEFORMATIONS IN CERTAIN RANGES OF THE GREAT BASIN 
CHARLES LAURENCE BAKER 
BDIPORTAGS Soe ok Ob A imei cat dee BAe eg de Ske ee oe 
REVIBWS.°5 12702) a) We re se Ria A We) yo pohly es ee a 
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