Zhe Journal of Geology 



Published on or about the following dates: February i, March 15, May 1, June 15, 

 August 1, September 15, November 1, December 15. 



Vol. XIX CONTENTS FOR OCTOBER-NOVEMBER, \9U No. 7 



THE IOWAN DRIFT - Samuel Calvin 577 



THE THEORY OF ISOSTASY Harmon Lewis 603 



SPECULATIONS REGARDING THE GENESIS OF THE DIAMOND - Orville A. Derby 627 



PRELIMINARY NOTES ON SOME IGNEOUS ROCKS OF JAPAN. IV - - S. Kozu 632 



FACTORS INFLUENCING THE ROUNDING OF SAND GRAINS Victor Ziegler 64s 



THE UNCONFORMITY BETWEEN THE BEDFORD AND BEREA FORMATIONS OF NORTHERN 



OHIO ----.----------- Wilbur Greeley Burroughs 655 



EDITORIAL - - ' - - - - - - - - - - T. C. C. 660 



REVIEWS - - - - - " 661 



RECENT PUBLICATIONS - 669 



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