8 GRANITIC ROCKS OF CORNWALL. [Ch. II. 



crystalline and non-fossiliferous masses, both compact and 

 schistose, which are usually associated together under different 

 arrangements, and intimately connected by frequent mineral 

 transitions. 



This proposition may appear to some to be inadmissible, 

 on the ground that the rocks thus brought together belong 

 to several distinct geological epochs : but, admitting this view 

 of the subject, (for, though it will be disputed hereafter, it is 

 immaterial at present,) still these rocks constitute such a 

 natural family, that they may be examined and described as 

 such, independently of all theoretical considerations concerning 

 the nature of their origin. Since this is a point that ought 

 to be satisfactorily established, it may be stated, for the sake 

 of the general reader, that Lyell admits that, " if we investi- 

 gate a large portion of a continent which contains within it 

 a lofty mountain range, we rarely fail to discover another 

 class, very distinct from either the subaqueous deposits or 

 volcanic rocks ; and which we can neither assimilate to de- 

 posits such as are now accumulated in lakes or seas, nor to 

 those generated by ordinary volcanic action." Again, he 

 adds, that " nothing strictly analogous to these ancient form- 

 ations can now be seen in the progress of formation on the 

 habitable surface of the earth ; nothing, at least, within the 

 range of human observation." * Since these remarkable form- 

 ations are so distinct from all other kinds of rocks, no great 

 disadvantage can arise from our treating of them under the 

 denomination of primary rocks ; it being always remembered 

 that this name is not used in a theoretical signification* 

 Having offered this apology for the employment of a term so 

 objectionable, we will now proceed to our task without farther 

 preamble. 



The primary rocks generally impart to a country a wild 

 and desolate aspect : here and there, indeed, landscapes of 

 great luxuriance and beauty present themselves; but the 



* Principles of Geology, vol. iii. p. 10, 11. 



