448 OnStnffa. 



generally curved. It is this bed which forms the ponderous cap 

 (as it is called) whicli crowns the summit of the grandj'a^ade. 



Although the great columnar bed occupies but a small por- 

 tion of the whole exterior face of the island, the columnar form 

 is perhaps predominant throughout the whoie. Yet it would be 

 equally difficult, as useless, to attempt to determine its propor- 

 tion to the amorphous part where they are irregularly mixed, as 

 they are at the northern and eastern sides. On these sides also 

 the division into distinct beds such as I have described above, is 

 by no means easy to trace, and possibly it does not exist. 



To those who have seen the beautifully regular columns of the 

 Giant's Causeway, those of StafFa will appear rude and compa- 

 ratively shapeless. They no where exhibit that accuracy of de- 

 sign which is so cons])icunus in the former, and are rarely seen 

 of any considerable length without some incurvation. But 

 their thickness is much greater, since tl.ey often attain a diame- 

 ter of four feet. They vary ])crj5Ctually in the number of their 

 angles, the pentagonal and hexagonal being the most common, 

 and those of an inferior number of angles being less common 

 than those of a superior. Their joints are very irregularly placed, 

 and are frequently wanting tlirough a considerable length. When 

 separated, the touching surfaces arc either flat, or marked by a 

 slight respective concavity and convexity. In many places, and 

 most conspicuously in the great cave, the angles of the upper 

 joint are considerably and obliquely truncated at the point of 

 contact with the lower one. But I did not perceive any in- 

 stance where a corresponding projection of the end of the in- 

 ferior angle rose to cover the truncation, a circumstance of such 

 frequent occurence at the Giant's Causeway. I may add, that 

 the articulated columns are most remarkable in the great cave, 

 and that the straightest columns generally exhibit the most fre- 

 quent articulations. The curved columns visible at the cave 

 called the Clamshell cave, extend for 40 or .50 feet without a 

 joint. 



The disposition of the variously curved columns above this 

 small cave, is perhaps one of the most striking features of the 

 whole island. But it will be time enough to speculate on the 

 formation of a curved basaltic column, when we have something 

 rational to offer en that of a straight one. 



A very extraordinary aggregation of columns lies off this cave, 

 forming a conical detached rock, corruptly called Boo sha la. 

 The Gaelic name Buachaille (BouxoAoj?) the herdsman, is com- 

 monly applied to conspicuous single rocks all over the country. 

 This rock consists of variously inclined columns resting against 

 each other, ^md m -meting till they^form a conical hotly, which 

 appears to riepose on a bed of carved and horizontal columns. 



It 



