244 RASAY. GEOLOGY. 



as there is no other method of reference, I must trust to 

 the map to point out the space it occupies. The dip is 

 every where to the westward, but varies in the quantity 

 of the angle. On the eastern side it is generally con- 

 siderable, averaging perhaps 40, while towards the west 

 it becomes less, and in some cases subsides as low as 

 to 10. As the dip of the gneiss is towards the east 

 where it lies near the sandstone, it is evident that they 

 occupy reverse positions. Where the red sandstone 

 terminates on the western shore it is followed by a white 

 sandstone in a manner that will be described hereafter. 



Red sandstone occurs in two other places in Rasay ; 

 and it is particularly interesting to trace these portions, 

 as their positions, while they are somewhat obscure, are 

 important, from the connexion which they establish 

 between the northern tract just described and an exten- 

 sive series of beds that will be shown to predominate in 

 Scalpa and to occupy a large part of Sky as well as of the 

 neighbouring mainland. 



The first of these, as being the nearest to the main 

 body, is a very small portion occupying a nameless point 

 in the map ; its dimensions do not exceed a few hundred 

 yards and it is accompanied by a portion of the usual 

 conglomerate. The angle of elevation of the beds, of 

 which the dip is also westerly, is scarcely 20 ; and from 

 that circumstance, as well as from the small quantity of 

 the rock visible, it is difficult to ascertain truly the direc- 

 tion, which however appears to be about N. by E. It is 

 equally difficult to determine the true relative place of 

 this portion of sandstone to the other strata, as it is 

 separated by a chasm from the white sandstone that 

 lies near it. If this be attempted by prolonging the 

 planes of the beds, it seems rather to be continuous 

 with than subjacent to that rock, but as it bears marks 

 of disturbance, and as the white sandstone is occa- 

 sionally irregular, that position may be considered as 

 accidental. We are at least entitled by analogy to class 



