DU NOYEK— NOTES ON THE GIANT S CAUSEWAY. 
two lowest, which occupy the central 
position of the clifl", are rudely and mas- 
sively columnar, and are sepai'ated 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 cHlF is composed partly 
of amorphous trap and a gi'oup 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 cliiF is traversed 
from its base to its summit by a whin 
dyke, fifteen feet thick, the strike of 
which is about north-west and soutii- 
east (Lign. 7). 
The projection in the coast directly 
south of the Causeway and overhang-ing 
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 tliickness, 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 colmnns in situ 
may be accounted for in two ways : 
