DU NOYEE — NOTES ON THE GIANT'S CAUSEWAY. 



two lowest, which occupy the central 

 position of the cliif, are rndely and mas- 

 sively columnar, and a.re separated from 

 each other by an irregular layer of 

 rotten black shale, which at one period 

 was searched for coal, and is still known 

 as the " coal-mine ;" the lower portion 

 of this shale is a dull brownish-red earth. 

 Above these columnar beds the re- 

 mainder of the cliff is composed partly 

 of amorphous trap and a group of small 

 columns, which are bent out of the per- 

 pendicular, being overlaid by a thin 

 layer of horizontal columns, which ter- 

 minate the chief section. 



At this locality the cliff is traversed 

 from its base to its summit by a whin 

 dyke, fifteen feet thick, the strike of 

 which is about north-west and south- 

 east (Lign. 7). 



The projection in the coast directly 

 south of the Causeway and overhanging 

 it, called " Ard snoot," is three hundred 

 and seven feet above the sea. It ex- 

 hibits two well-marked columnar beds, 

 most probably the representatives of 

 those at the Chimney-headland. They 

 appear to be of equal thickness, but the 

 upper bed, which forms the summit of 

 the cliff, exhibits small, well-formed, but 

 partially bent, or irregularly bulged 

 columns ; while those of the lower bed 

 are unusually large, rudely formed, and 

 more vertical. 



From the observations which I have 

 been able to make, it would appear that 

 the bending of basaltic columns in situ 

 may be accounted for in two ways : 



li 



m 



