54 GENERAL OUTLINES AND 



remarks, find abundant reasons for not trusting further 

 to that aid than is absolutely indispensable: and, to 

 the student in geology, no safer rule can be given, 

 than that he can be certain of nothing which he has 

 not touched. His eye may deceive him, but he will 

 never be misled by his hammer. 



It is a common remark, that granite occupies the 

 highest parts of a country, and that it produces those 

 pinnacled and serrated summits so well known to those 

 who have visited the Alps, or have, in our own coun- 

 try, seen the mountains of Arran. Yet a geologist 

 who shall trust to this feature as characteristic of gra- 

 nite, will be deceived much oftener than he will 

 form a correct judgment; as that rock presents every 

 variety of outline, and as many others assume the 

 spiry and serrated form. The mountains about Loch 

 Etive in Scotland, are characterized by the simple 

 conical outline, which is particularly marked .in 

 Cruachan ; and they are unvaried by a single serrature 

 or pinnacle. The extensive ridge which surrounds 

 the sources of the Dee, forming the loftiest tract of 

 mountain land in Britain, presents a series of heavy, 

 rounded, elevations ; on which, if we except a few of 

 the cairns that are scattered over Ben Avon and 

 others of the group, not an irregularity exists to 

 indicate the nature of the rock, which is never- 

 theless a continuous mass of granite. In Cornwall, 

 in Galloway, and in Sutherland, it offers the same un- 

 interesting aspect; while, in many parts of Aberdeen- 

 shire, it occupies the lowest grounds, presenting large 

 tracts of a surface as level as that which has been 

 supposed to characterize districts of secondary rocks. 



Thus the observer who may be so far induced to 

 trust to the serrated and spiry outline, as to exclude 

 from granite, or to neglect, those tracts which do riot 



