CONTENTS OF VOLUME XIX vii 



PAGE 



The Differentiation of Keweenawan Diabases in the Vicinity 



of Lake Nipigon. E. S. Moore ...... 429 



Genera of Mississippian Loop-Bearing Brachiopado. Stuart 



Weller ........... 439 



Physiographic Studies in the San Juan District of Coloroda. 



Wallace W. Atwood ........ 449 



The Variations of Glaciers. XVI. Harry Fielding Reid . . 454 

 Petrological Abstracts and Reviews . . ... .462 



Reviews ........... 469 



NUMBER VI 



Preliminary Statement Concerning a New System of Quater- 

 nary Lakes in the Mississippi Basin. Eugene Wesley Shaw 481 

 Gravel as a Resistant Rock. John Lyon Rich .... 492 



The Cretaceous and Tertiary Formation of Western North 



Dakota and Eastern Montana. A. G. Leonard . . . 507 



On the Genus Syringopleura Schuchert. George H. Girty . 548 



Preliminary Notes on Some Igneous Rocks of Japan. I. S. Kozu 555 

 Preliminary Notes on Some Igneous Rocks of Japan. II. S. 



Kozu ........... 561 



Preliminary Notes on Some Igneous Rocks of Japan. III. S. 



Kozu ........... 566 



Reviews ........... 576 



NUMBER VII 



The Iowan Drift. Samuel Calvin ...... 



The Theory of Isostasy. Harmon Lewis ..... 



Speculations Regarding the Genesis of the Diamond. Orville A. 



Derby ........... 



Preliminary Notes on Some Igneous Rocks of Japan. IV. S. 



Kozu ........... 



Factors Influencing the Rounding of Sand Grains. Victor 



Ziegler ........... 645 



The Unconformity Between the Bedford and Berea Formations 



of Northern Ohio. Wilbur Greeley Burroughs . . -655 



577 

 603 



627 



632 



