PAPERS ON MOUNTAIN STRUCTURE. Gil 



After some general aiinouncements the scientific work of the meeting was 

 declared in order, and acting President Winchell announced the first paper 

 upon the printed program : 



THE STRUCTURE OF A PORTION OF THE SIERRA NEVADA OF CALIFORNIA. 



BY GEORGE F. BECKER. 



The communication was briefly discussed by George M. Dawson. It is 

 printed among the memoirs of this volume, forming pages 49-74. 



The second paper was — 



NOTE ON THE GEOLOGICAL STRUCTURE OF THE SELKIRK RANGE. 



BY GEORGE M. DAWSON. 



This was discussed by C. D. Walcott, J. W. Spencer, and G. K. Gilbert. 

 It forms pages 165-176 of this volume. The discussion by Messrs. Spencer 

 and Gilbert is appended to the paper. Mr. Walcott's remarks were as fol- 

 lows : 



DISCUSSION ON THE GEOLOGICAL STRUCTURE OF THE SELKIRK RANGE. 



BY C. D. WALCOTT. 



Of the 25,000 to 40,000 feet of strata of the Castle Mountain and Bow River series 

 included by Dr. Dawson in the Cambrian I have heretofore referred the lower por- 

 tion, beneath the zone of the Olenellus fauna the Bow River series, to the Algon- 

 kian. While, as Dr. Dawson claims, there is no improbability that Cambrian life 

 might be found in the lower series, yet the Olenellus fauna was the oldest known, and 

 for convenience the strata beneath were referred to the Algonkian ; still, from the fact 

 that during the past summer I have found the Olenellus fauna to range through 1,000 

 feet of limestone and 250 feet of superjacent shales in Vermont, it is exceedingly 

 probable that it had an extensive range in the quartzites of the Bow River series and 

 also in the corresponding series of the Wasatch range, which was studied by the For- 

 tieth Parallel survey and subsequently by myself. Owing to this I shall not offer 

 serious objection to including the Bow River series in the Cambrian. A similar series 

 has been described by Mr. Gilbert in Utah and by Dr. Peale in Montana. 



The next paper was — 



THE OVERTHRUST FAULTS OF THE SOUTHERN APPALACHIANS. 

 BY C. WILLARD HAYES. 



It was discussed by G. K. Gilbert, C. D. Walcott, W. M. Davis, and 

 Bailey Willis, and forms pages 141-154, with plates 2 and 3, of this volume. 



