ON THE BASALTIC COUNTRY IN IRELAND. 1 65 



between the Gianfs Causeway and Dunseverick I now limit 

 myself, as all the strata composing it emerge between these 

 two points. 



As we proceed along the coast from the Giant' 1 s Cauxeioay Rise and fallaf 

 eastward, we perceive the whole mass of strata ascend gra- tlie,trata - 

 dually, culminate at the northern point of the promontory, 

 and then descend more rapidly, as the land falls away to the 

 sonth-east, until having traced them across the face of the 

 precipice we see them immerge separately at and beyond 

 Port moon zrhyn dikes. 



The western side of the promontory is cut down perpemh- whyn dikes, 

 cularly, by eleven ichyn dikes; the intervals between them 

 are unequal, but they all reach from the top of the precipice 

 to tl:e water, out of which some of them again emerge in 

 considerable fragments; they are all constructed of horizon- 

 tal prisms, which are. strongly contrasted witfy the vertical 

 pillars of the strata through which they pass. 



One of the dikes at Port Cooan, on Bengore, half a mile 

 from the Giant's Causeway, is very beautiful ; an insulated 

 rock about 160 feet high, and 20 in diameter, stands per- 

 pendicular in the middle of a small bay ; the main body of 

 the rock is similar to the contiguous consolidated masses; 

 but on the east side a singular whyn dike is joined to it, 

 composed (as they often are) of several walls agglutinated 

 together, with wall-like fragments of other parts of the dike 

 emerging at their base ; the solid mass of dike is seen cut- 

 ting down the precipice to the southward at 150 yards 

 distance. 



Depressions of the Strata, 



Soon after we have passed the last of our whyn dikes at Depressions of 

 Port Spapia, (a name derived from a vessel belonging to the the slrata « 

 Spanish Armada having been driven ashore in that creek), 

 we discover a new and curious circumstance, viz. that the 

 western half of the promontory has sunk or subsided be- 

 tween thirty and forty feet, without the slightest concussion 

 or derangement of the parallelism of the strata. 



Two other depressions appear as we proreed onwards, 

 •ne at Portmoon, and the other at the angle where the pro- 

 montory Legins to project from the rectilineal coast; these 



however 



