POSITION OF STRATIFIED ROCKS. 



49 



curved strata of slate, that belong to the transition 

 class of rocks, and which occur near St. Abb's 

 Head. (Fig. 14.) 



FIG. 14. 



There are sixteen distinct bendings in the course 

 of six miles. Now were those strata extended and 

 restored to their original horizontal position, in place 

 of being subtended, as they now are, by a horizontal 

 base of six miles, they would be subtended by 

 a horizontal base of about ten miles and a half. 

 Whence this contraction of base ? May it not be 

 explained, as before, upon the supposition, that the 

 globe has undergone an increase of density, and 

 therefore a diminution of magnitude, since those 

 strata were deposited ? and as the horizontal base 

 which subtended the primitive strata of gneiss when 

 they were deposited was fully three times greater 

 than that which now subtends them, whereas the 



