574 



and which joins the Spring Creek where the main 

 limestone is exposed in the northern banks. 

 (c) A few hundred }'-ards further to the eastward of the 

 last, where the siliceous limestones are repeated at 

 the next turn of the creek to the northward ; the 

 creek, in this stretch of its course, following 

 apparently the line of the fault. Stratigraphical 

 evidence of the fault-plane is seen at the turn of 

 the creek just mentioned, where on the left bank 

 of the stream the Tapley Hill slates dip W. at 35°, 

 while the siliceous limestones (much distorted) on 

 the opposite bank dip a few points north of west 

 at 55°. 



The fact that each of the limestone outcrops on this side 

 of the mount is turned back upon itself and bent in an east- 

 ward direction suggests that the least resistance existed on 

 that side. On the western side there was the great buttress 

 of the quartzites of the Black Range, and to the northward 

 the equally thick and compact purple-slates, which also failed 

 to yield to pressure, while the more extensive and important 

 subsidences of the eastern area (which formed the eastern 

 plains) allowed the gravitating segments to find ex- 

 tension in that direction. The exigencies of the case 

 doubled back the beds against the normal strike, but the 

 pressure could not have been severe, as the beds do not 

 pass into the anticlinal and synclinal folds, but maintain, on 

 the whole, a comparatively uniform dip to the west ; while 

 crush-rock, which is such a marked feature of the disturbed 

 field on the south-eastern side 'of the mount, is apparently 

 absent in the north. In some instances, however, as in the 

 case of the siliceous limestones that abut against the north- 

 eastern angle of the mount, the grain of the stone is much 

 flexured. 



4. Tectonic Features of the Eastern Side of the Mount. 



The mount is not exactly equilateral. The greatest 

 transverse diameter is along a line that intercepts the highest 

 point of the mount, and is situated about two miles to the 

 northward of Melrose. The great fault-plane that deter- 

 mines the eastern face of the mount is angulated at about 

 the same spot. There are probably two fault-planes, which 

 intersect at an obtuse angle, the one trending south-westerly 

 and the other in a north-westerly direction. The latter 

 follows the base of the north-eastern face of the mount where 

 the main quartzite comes down to the plain, but the exact 

 line of fault is obscured by a wide talus, composed chiefly of 

 quartzite fragments, which forms a gentle slope, extending 



