The Coast-line 



sisted almost entirely of blocks of chalk and flint, similar 

 to the material of the cliffs, but included a few of basalt, 

 which, however, was finer grained than that of Black 

 Point. 



There was a band of this fine-grained basalt running 

 up the cliff in an almost vertical direction. It was about 

 8 feet in width, and cut through the beds of chalk in 

 a manner similar to that of the larger mass previously 

 seen, while on each side the chalk was saccharoid, but 

 only for a distance of 3 inches from the edge of the 

 basalt. 



This basalt had evidently come up from below in a 

 molten condition, and had filled a fissure or crack in the 

 chalk. It was in fact a "dyke," and the larger mass at 

 Black Point appeared to be of a similar nature. 



Continuing in the direction of Clifftown, we noticed 

 that the cliff became somewhat lower, and that the dip of 

 the chalk first became less and less and then changed its 

 direction to north-west. It then increased very rapidly 

 until it reached an angle of 70, which continued to within 

 a short distance of the village. There then appeared 

 beneath the chalk a bed of sandstone of a grayish-green 

 colour, and containing numerous dark-green, almost 

 black when wet, grains of a mineral called glauconite. 

 This sandstone was found to contain numerous well- 

 preserved fossils amongst others the molluscs Pecten 

 asper and Exogyra columba, both of which are found in 

 the Upper Greensand a rock which occurs immediately 

 below the chalk in the south of England and other 

 places. 



From its position underlying the chalk, and the 

 fossils, which it contained, we concluded that this rock 



85 



