CONTENTS 



Page 

 The problem of the pre-Cambrian ; Presidential address by Charles Rich- 

 ard Van Hise 1 



beginning and recession of Saint Anthony Falls ; by Frederick W. Sar- 



DESON 29 



Wind erosion in the plateau country ; by Whitman Cross 53 



Rock-floor of intermout plains of the arid region ; by Charles R. Keyes. . 63 

 Occurrence of proustite and argentite at the California mine, near Monte- 

 zuma, Colorado ; by Frank R. Van Horn 93 



Probable age of the Meguma (gold-bearing) series of Nova Scotia; by J. 



Edmund Woodman 99 



delations of radioactivity to cosmogony and geology ; by George F. Becker. 113 

 Conglomerate formed by a mineral-laden stream in California ; by Ralph 



Arnold and Robert Anderson 147 



Lower portion of the Paleozoic section in northwestern New York ; by H. 



P. Cushing 155 



Topaz-bearing rhyoljte of the Thomas range, Utah ; by Horace B. Patton. 177 



Outlines of hydrology ; by W J McGee 193 



Geological history of the Redstone quartzite ; by Frederick W. Sardeson . . 221 



Nebraska "loess man" : by B. Shimek 243 



Paleozoic and associated rocks of the Upper Yukon, Alaska ; by Alfred H. 



Brooks and E. M. Kindle 255 



Geologic reconnaissance of the Porcupine valley, Alaska ; by E. M. Kindle. 315 



Giant springs at Great Falls, Montana ; by Cassius A. Fisher 339 



Glacial periods and their bearings on geological theories ; by A. P. Cole- 

 man 347 



Strata containing the Jurassic flora of Oregon ; by J. S. Diller 367 



Paleozoic and Mesozoic of central Wyoming ; by N. H. Darton 403 



Shoreline studies on lakes Ontario and Erie ; by Alfred W. G. Wilson .... 471 



Mine waters and their field assay ; by Alfred C. Lane 501 



Proceedings of the Twentieth Annual Meeting, held at Albuquerque, New 

 Mexico, December 30 and 31, including Proceedings of the Ninth Annual 

 Meeting of the Cordilleran Section, held at the same place and time; 



Edmund Otis Hovey, Secretary 513 



Session of Monday, December 30 514 



Report of the Council 514 



Secretary's report 514 



Treasurer's report 517 



Editor's report 519 



Librarian's report 520 



Election of Ofiicers 521 



Election of Fellows 522 



Memoir of James Merrill Safl:ord (with bibliography) ; by J. J. 



Stevenson 522 



Memoir of Angelo Heilprin (with bibliography) ; by Herbert E. 

 Gregory 527 



