PAPERS READ BEFORE CORDILLERAN SECTION 565 



At 2 o'clock the Section reconvened, Dr H. W. Fairbanks in the chair, 

 and the following papers were read and discussed : 



GEXESIS OF ORE DEPOSITS IX BOULDER COUNTY, COLORADO 

 BY RUFUS M. BAGG, JR. 



[Absti^act] 



The geolog)'' of Boulder county was outlined, and the formation of veins was 

 considered. A description was given of the occurrence of fissure veins along 

 irregular fracture zones which, after faulting, have been secondarily filled with 

 solutions and sublimation products, chiefly the tellurides of gold, mercury, and 

 the sulphide of iron, marcasite. The genesis of these rich ore pockets was dis- 

 cussed, A description of some of the principal mines and a summary of field 

 observations when examining mines in the district were given. 



LEUCITE HILLS OF WYOMING 

 BY .T. F. KEMP AND W, C. KNIGHT 



Mr Knight presented this paper before the Cordilleran Section at the 

 same time Professor Kemp read it at the Washington meeting. It is 

 printed as pages 305-336 of this volume. 



MECHANICS OF IGNEOUS INTRUSION* 

 BY R. A. DALY 



This paper is published in the American Journal of Science, volume 

 XV, April, 1903, page 269 et sequitur. 



The following papers were read b}^ title : 



PROBABLE CA USE OF WATER FLOW IN THE MINES OF CRIPPLE CREEK, 



COLORADO 



BY RUFUS M. BAGG, JR. 



PA DDLES OF SHA ST A SA UR US 



BY JOHN C. MERRIAM 



QUATERNARY OF THE MIDDLE COAST RANGES OF CALIFORNIA 



BY ANDREW C. LAWSON 



STRUCTURAL SECTION OF A BASIN RANGE 



BY GEORGE D. LOUDERBACK 



An abstract of the paper is printed in the Journal of Geolog}^, volume 

 xi, pages 102-103. 



The Section then adjourned. 



* Presented by Andrew C. Lawson. 



