Contents of Volume XXX 



NUMBER I 



PAGE 



An Outline OF THE Geology OF New Zealand. W.N.Benson. . i 



PENNSYLVANL4N STRATIGRAPHY OF NORTH CENTRAL TeXAS. Raymond 



C. Moore and Frederick B. Plummer i8 



Pleistocene Mollusca from Northwestern and Central Illinois. 



Frank Collins Baker 43 



The Muddy Mountain Overthrust in Southeastern Nevada. 



Chester R. Longwell 63 



Growth-Stages of the Blastoid, Orophocrinus Stellijormis. F. A. 



Bather 73 



Possible Silurian Tillite in Southeastern British Columbia. 



Francis P. Shepard 77 



Reviews 82 



NUMBER II 



The Great Fault Troughs of the Antilles. Stephen Taber . 89 

 The Character of the Stratification of the Sediments in the 



Recent Delta of Eraser River, British Columbia, Canada. 



W. A. Johnston 115 



The Structural Relation of the Purcell Range and the Rocky 



Mountains of Canada. Francis Parker Shepard . . . . 130 

 Aspects of Ontogeny in the Study of Ammonite Evolution. 



A. E. Trueman 140 



A New Phytosaur from the Trias of Arizona. Maurice G. Mehl 144 

 Adapting a Short-Bellows, Roll-Film Kodak for Detail Work 



IN THE Field. Chester K. Wentworth 158 



Segregation Granites. Alfred C. Lane 162 



■On the Presentation of Igneous Rocks in Triangular Diagrams. 



Albert Johannsen 167 



Petrological Abstracts AND Reviews 170 



Reviews 175 



NUMBER III 



The Reaction Principle IN Petrogenesis. N. L. Bowen . . . 177 

 An Outline of the Physiographic History of Northeastern 



Ontario. W. H. ColUns 199 



A New Occurrence of Crystobalite in California. Austin F. 



Rogers 211 



