458 



lumnar bafalt, and a red ochrous fubflancc, no doubt, decompofed 

 bafalt. * 



At Carrickarede, this arrangement is changed into a folid unflratified 

 mafs of columnar bafalt, 250 feet high, the alternate mafs I have pafled 

 being about 400 ; above this the hill or mountain of Knockfoghy is com- 

 pofed of ftrata of columnar bafalt alternately with another fpecies of 

 bafalt (hitherto unnoticed, though common with us) of the fame grain, 

 but of quite different internal conftruftion. 



The coafl; now lowers for a few miles to the caftle of Dunfevrick, 

 near which the bold promontory of Bengore projefts into the ocean, 

 difplaying with great magnificence the various Strata of which it is com- 

 pofed.f To enumerate them all would be too tedious. I fhall only obferve, 

 that the Stratum which (at the northern point of the promontory where 

 they culminate) is the 8th from thd water, and 250 feet above it, is 

 compofed of bafalt pillars 44 feet long. At its eaftern interfeiftion with 

 the plane of the fea, it forms the bafe of two beautiful iflands, called 

 Beanyn Daana, and at its weftern interfeftion, or immerfion, two miles 

 diflant, it forms the Giant's Catifeivay. 



For many miles weftward, the face of the rock is compofed of ftrata 

 of table bafalt, feparated from each other by ochrous layers ; this ar- 

 rangement 



* I have, in a memoir read before the Royal Society, Edinburgh, assigned my reasons 

 for supposing the red ftrata, which make fo conspicuous a figure in the faces of our preci- 

 pices, to have been once pure basalt. 



f Thefe ftrata are fixteen in number, all afcending to the northward, in an angle greater 

 than that made by the irregular furface of the promontory with the horizon ; of thefe, ten 

 only reach the face of the precipice at Plejiin, the remaining fix baflet or vanifh in the air, 

 before they arrive at it ; but if the fa5ade be purfued to Portmoon, i mile S. E. they will 

 be found to appear fucceflively on its fummit, then dipping rapidly, and regularly, until 

 they immerge beneath the water lov/<irds Dunfuverici, the firft ten having immerged in fuccef- 

 lion about Fortmoon. 



Traced weftward, their dcfcent is not fo rapid, as the promontory, on this fide, does 

 not fall off fo much to the fouthward ; but the three lower of the fix, and part of the 

 fourth, appear often on the fummit, wherever the height of the precipice is fufficient to 

 ^ave room for them, and each invariably in its own proper place. 



