THE BANNOCK OVERTHRUST 705 
the lines formerly developed. In the vicinity of Meade Peak near 
the south end of the Preuss Range, where the best opportunity has 
been found to study the character of the deformation, a well defined 
syncline has been developed almost directly under a sharp anticline 
in the overlying beds. The question is raised as to whether or not 
the deformation of the plane of the thrust may be due to the load 
of the overlying anticlinal mass rather than lateral pressure. The 
dip of the fault plane that branches from the main fault and 
extends under the east flank of Meade Peak (Fig. 4) is steep and in 
places appears to be inclined westward. These facts are regarded 
as unfavorable to the latter view. 
PARALLEL ASSOCIATED THRUSTS 
Extensive overthrust faults are by no means a novel feature of 
the region, and faults have been previously described immediately 
east and west of the trace of the Bannock. The position of these 
faults has been shown upon Fig. 1. 
Western Wyoming.—Peale (18a), Veatch (24d), and Schultz 
(10a) have described portions of the great Absaroka thrust, the 
trace of which lies about 8-25 miles east of the state boundary. 
The throw in two localities (24e) described by Veatch is 
over 15,000 and 20,000 feet respectively. In the latter place 
rocks of Triassic age rest upon rocks of middle Cretaceous age— 
specifically, the Thaynes limestone upon the Oyster Ridge sand- 
stone member of the Frontier (24f) formation. 
North of these areas Schultz reports that the throw is of the 
same amount. The Darby, another overthrust which has been 
mapped by Schultz (20b), has a maximum exposed _ horizontal 
displacement of 3 miles. Labarge Mountain, which is a part of 
the overthrust block overlying the plane of the Darby fault, is 
composed in part of rocks of Cambrian age. This is, according to 
Schultz,* the easternmost exposure of the Cambrian rocks which 
make up the greater part of the Bear River Range in Utah and 
Idaho, a distance of over 50 miles to the west. It is possible, then, 
that the rocks present in Labarge Mountain may have been derived 
from the region of the Bear River Range. 
1 Personal communication. 
