!212 The Rev. W. Conybeare on 



nificent range of promontories in the neighbourhood of the Giant's 

 Causeway, commences. Since the chalk, which is here placed on 

 the same level with the highest of these strata, must certainly in 

 its regular place occur beneath the lowest, and since the whole series 

 has been ascertained considerably to exceed 400 feet in thickness, 

 the subsiden'ce of the basaltic mass at this point must have been 

 very great. 



The neighbourhood of the causeway, with all its remarkable 

 features, its superb storied facades, distinguished by a double order 

 of columns, its whin dykes and its caverns, have been so fully and 

 ably described by Dr. Richardson in the Philosophical Transactions, 

 that they are already familiar to every reader interested in such 

 subjects. His list of the strata here ascertained has been already 

 given, page 177. On the strand near the mouth of the Bush, are 

 two parallel ledges of chalk and basalt. 



The appearances of the cliffs between Bushfoot Strand and 

 Portrush Strand, are so similar to those which we have already 

 found frequent occasion to notice, that this part of the section does 

 not appear to require further elucidation. Near the termination of 

 the chalk cliflf on the west, a very inexplicable phenomenon pre- 

 sents itself; a large spherical mass of basalt, appearing to be com- 

 pletely enveloped in the chalk. 



The singular peninsula of Portrush demands more particular at- 

 tention ; a long line of strand separates it on either side from the 

 cliffs which rise at about the distance of a mile to the east and 

 west. 



The peninsula itself, which may be about a mile in circum- 

 ference, is fenced with low cliffs on the west, north, and east ; 

 those on the west present a rudely prismatic greenstone ; those on 

 the north and east tabular masses of greenstone, overlying, and in 



