ABSTRACTS OF PAPERS 99 



of uplift and presents very interesting details of structure. The fold lingers 

 into several small folds as it plunges northeast, which are also faulted. A 

 colored map of the area and structure sections will be presented. 



Presented extemporaneously. 

 Discussed by H. F. Eeid and the author. 



RELATION OF DEEP-SEATED FAULTS TO SURFACE STRUCTURE IN THE 

 REGION NORTHEAST OF THE YELLOWSTONE PARK PLATEAU 



BY W. T. THOM, JR. 1 



(Abstract) 



This paper reviews briefly what is known concerning the great thrust-faults 

 which feature the front of the main Cordilleran belt in Montana and Wyoming, 

 and illustrates the structural features of the irregular uplifts of central Mon- 

 tana by means of structure contours drawn on the base of the Upper Creta- 

 ceous series. This structure contour map indicates the existence of marked 

 structural trends and strongly suggests that the development of the existing 

 surface structural feature has been controlled by fundamental faults. The 

 existence of these fundamental faults and their geologic importance is seem- 

 ingly further indicated by the areal distribution and development of certain 

 formations and by the location of the several important areas of former igne- 

 ous activity which exist in central Montana. 



Presented by title. 



POSSIBLE TILLITE AT LEVIS, QUEBEC 

 BY ROBERT W. SAYLES 



(Abstract) 



In the Levis shale of the Beekmantown formation at Levis, Quebec, there 

 occurs a bed which appears to be of glacial origin. The evidence of such 

 origin is found in the remarkable similarity to beds of sublacustrine tills and 

 tillites intercalated in the Pleistocene glacial clays and in glacial slates and 

 shales of older glaciations, especially as found in the glacial clay at Woodsville, 

 New Hampshire, and at Squantum, Boston Harbor. This bed was found by 

 the author on September 23, 1921, while on the way to examine the limestone 

 conglomerates at Levis with T. H. Clark, of Harvard University. It can be 

 seen in the cliff opposite the lumber yard of C. H. Jackson & Company, five 

 minutes' walk down the river from the railway station. 



Like the sublacustrine tills and tillites, this bed is composed of a till matrix 

 in which are imbedded blocks and contorted masses of the underlying banded 

 shale, together with boulders and rock fragments with rounded and angular 

 and subangular shapes, lying at all angles and with no sorting or stratification 

 visible. The bed itself is very uneven in thickness and the upper contact with 

 the overlying shale is uneven and wa^y, just as in other cases of such sub- 



1 Introduced by David White. 



