IN GLEN TILT. S43 



along the slope of the mountain on the south side of the val- 

 ley, preserve a considerable degree of uniformity in their 

 stretch and dip, and vary their position slowly by large undu^ 

 lations ; on the otlier hand, some stratified rocks on the south- 

 ern bank of the river, which appear to be connected with this 

 great body of strata, but are adjacent to the main rocks of sie- 

 nite, exhibit great varieties of position within a small distance, 

 and rapid changes in the curvature of their planes. (Pa- 

 rag. 9, and from 19 to 27, compared with 43, 45, 46, 50, 

 70, 89.) 



107. Adjacent to some spots, where the main rocks of sie- 

 nite, and the great body of strata, appear either in contact, or 

 near to each other, there are numerous masses composed of 

 substances which are stratified, and closely resemble those that 

 form the great body. These masses do not touch each other 

 at the present surface, and sections of the rocks in every direc- 

 tion prove that many of them must be completely separate. 

 The smallest of these masses are not larger than a hazel-nut ; 

 the larger would measure several feet every way. From the 

 numerous sections of these masses, afforded by the indented 

 and water-worn surfaces of the rocks, we farther learn, that the 

 concealed surfaces of the masses are rough ; that their shapes 

 are irregular, and that they often terminate in sharp angles. 

 In position, as to stretch and dip, they often differ extremely 

 from the great body of strata, as well as from each other ; and 

 this difference prevails even among such as lie nearest toge- 

 ther. (Parag. from 51 to 53, 76, from 78 to 81, 84, 87, 88, 

 90.) 



108. Some of these masses rest upon the main rocks of sie- 

 nite. (Parag. 52, 53, 79, 87, 88, 91.) 



109. The intervals between such of these masses as appear 

 adjacent on the present surface, vary in breadth, from the small 



X X 2 fraction 



