Dr. Mac Culloch on Staffa. 505 



To those who have seen the beautifully regular columns of the 

 Giant's Causeway, those of Staffa will appear rude and compara- 

 tively shapeless. They no where exhibit that accuracy of design 

 which is so conspicuous In the former, and are rarely seen of any 

 considerable length without some incurvation. But their thickness is 

 much greater, since they often attain a diameter of four feet. They 

 vary perpetually in the number of their angles, the pentagonal and 

 hexagonal being the most common, and those of an inferior num- 

 ber of angles being less common than those of a superior. Their 

 joints are very irregularly placed, and are frequently v/anting 

 through a considerable length. When separated, the touching 

 surfaces are 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 trun- 

 cated at the point of contact with the lower one. But I did not 

 perceive any instance where a corresponding projection of the end 

 of the inferior angle rose to cover the truncation, a circumstance of 

 such frequent occurrence 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 frequent 

 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 featui'es 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 on 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 (bouxoAo??) the herdsman, is commonly ap- 



VoL. II. 3 s 



