MULL. GEOLOGY. 



that I have in this, as in similar cases, adopted the 

 method most conducive to the principal object; the geolo- 

 gical description. This consists in assuming the several 

 rocks in a certain order from the lowest to the highest, 

 and tracing each separately in its course through the 

 several parts of the country. 



With the single exception of Arran, this is the only 

 one of the Western islands in which granite occurs, if 

 I may also except the veins of this rock which traverse 

 gneiss. It occupies a portion of the western and southern 

 point of the island, being part of the district called the 

 Ross, (or promontory), and, as I have formerly remarked, 

 it extends even to the neighbouring shores of lona. This 

 portion may be denned by a line drawn between Sui 

 and Ardchivoaig ; its interior course being irregular, and, 

 for want of more points of reference, unassignable. The 

 granite forms round this rude coast a barrier of rocks, 

 often naked, and even more so in appearance than reality, 

 from the glaring distinction which their colour gives them. 

 It is elevated into numerous round hills of no great height, 

 and seeming indeed, in this high and mountainous country, 

 much lower to the eye than their measurement shows. 

 The highest do not probably exceed 800 feet, and in 

 general they are much lower; while their unequal posi- 

 tions with respect to the coast tend to produce the very 

 indented outline it here exhibits. This rock, like most others 

 of its species, is so irregular in structure that it cannot 

 be said to assume any one in particular. The most remark* 

 able is the laminar, the laminae, when inclined, having often 

 at first sight the appearance of beds. They are frequently 

 vertical, and are generally split by fissures in different 

 directions, whence they sometimes present rudely prismatic 

 forms. Occasionally they are of great size. The measure of 

 one'was forty feet in height by twenty or more in breadth ; 

 while another, of much less breadth, measured fifty- 

 four feet in length. Entire blocks of very considerable 

 though inferior dimensions, are numerous. The grea>t 



