82 ON THE CONVOLUTIONS OF STRATA, 



upon the right, on which Fast Castle stands in fig. 1. Plate I., 

 exhibits also one of the convolutions concave downwards, 

 and similar to that of the Brander Cove, seen on the left. 

 Plate III. represents another rock of the same coast, at a 

 place called Whapness, near Gun's Green, in the neighbour- 

 hood of Eyemouth. Here there are four bendings ; two con- 

 vex upwards, and two convex downwards, lying close to each 

 other; and fig. 2. Plate I., represents a rock in the same neigh- 

 bourhood, in which a variety of convolutions are distinctly seen. 



We have thus a specimen of that part of the coast which con- 

 sists of killas; the whole being a succession of similar bendings, 

 alternately concave and convex upwards ; and the curvature 

 of the mass is, in general, (as Mr Playfair has well obser- 

 ved, Illustrations, art. 204.) simple ; that is to say, these bend- 

 ings are performed in one direction only, and round axes that 

 seem to lie horizontally, and parallel to each other. 



These strata, in common with all those of killas, seem to 

 have been originally deposited in a position nearly horizontal, 

 and many of the particular beds represented in these sketches, 

 possess that peculiar undulation on their surface which we 

 meet with on a sand} r beach, when the tide has left it, and 

 which affords the most unequivocal indication of aqueous de- 

 position. There is reason to believe also, that the strata, con- 

 stituting these convolutions, though now detached from each 

 other, have at one period lain in continuit}', and horizontally ; 

 that by the exertions of some powerful mechanical force, they 

 have been compelled to assume their present contorted shape ; 

 that their continuity still exists below, and would be seen, could 

 we penetrate into the mass under the level of the sea ; the in- 

 terruption of their continuity upwards, having arisen from a 

 removal of part of the rock, by some of those revolutions which 



have 



