152 PROCEEDINGS OF THE 



is very close-grained, and is capable of taking a high polish, and is, 

 therefore, much sought after for cvirling stones. 



The columns are said to be devoid of the ball-and-socket-like 

 arrangement prevailing among those of the Giant's Causeway; but 

 in the smaller columns I have seen it distinctly, though in the 

 larger it is not noticeable ; and, in my opinion, in these we might 

 rightly expect it to be absent, for larger masses in the molten state 

 would be more likely to present flat surfaces than concave and 

 convex ones. 



That this rock was thrown up molten there can be no doubt, for 

 in the rock itself there are minute crystals of quartz, not found in 

 " drusy " cavities, but really imbedded in the body of the rock, 

 placing the matter past doubt that they were formed when the 

 rock was protruded from the " fiery depths profound." 



The columns into which the rock is formed attain to various 

 proportions. The largest one which I measured Avas seven and a- 

 half feet in diameter, and eighty feet in length, without visible 

 break or joint. In some cases these immense monoliths are found 

 lying upon the shore at the foot of the cliff, from which they have 

 fallen, while as large masses would seem desirous of following their 

 example, for some that I examined were supported only on the 

 base, and had a distinct lean outwards. You may be assured this 

 leaning appearance does not add either to the security or the 

 comfort of the visitor, as he jumps from one rock to another on 

 the beach below. The mass of the columns do not stand straight 

 up. As far as I could judge, they have a lean outwards to the 

 north ; and at a place called the Barestack, where the cliffs start 

 from the water's edge, and soar upwards for some 600 feet, the 

 visitor is in momentary dread of being crushed by some huge 

 column which overhangs the deep. At the base of the cliffs great 

 masses of columns have fallen, and assumed in some cases grotesque 

 forms. 



The terraces and caves to be afterwards mentioned are both 

 alike due, in a great measure, to trap dykes which intersect the 

 island from north to south. Where the trap divides the columns, 

 the character of the syenite is changed considerably, being more 

 liable to crumble; in fact, by mere pressure of the hand it breaks 

 down. Where these trap dykes traverse the length of the island, 

 and penetrate to the surface, the terraces are formed, and in some 

 cases, as in those seen by the map, their wear, by means of water, 



