TRANSITION ROCKS. 125 



stance can more decidedly concur with definition. In the Alps, 

 Dr Berger must have learnt what primitive granite meant; yet 

 not a doubt escapes him, of the Cornish being any thing else. 

 Distinctions either do, or do not exist ; if they do, character 

 must be attended to ; if they do not, it is quite unnecessary to 

 add the terms Secondary and Tertiary to a substance posses- 

 sing every attribute of a primary variety, merely because the 

 structure of an adjoining rock does not accord with a specific 

 theory. 



Grauwacke, or, as I shall in future call it, Killas, I have be- 

 fore noticed, is a rock composed of fragments more or less 

 comminuted, which must have existed in another state before 

 they assumed their present arrangement. Along with the 

 strata formed of these, beds of limestone are found, containing 

 indications of organic remains. These are not confined solely 

 to the limestone, they occur also in the killas ; a fact which 

 may be witnessed at any time, either in the neighbourhood of 

 Coniston *, or on the right bank of the Blackwater, a little be- 

 low Fermoy, in the county of Cork, (Nos. 66, 67.) The for-: 

 mation of this class of rocks was therefore subsequent to the 

 formation of living animals, whose existence is supposed to be 

 proved by the occurrence of organic remains in the composi- 

 tion of the rock. 



In Cornwall, in Westmoreland, in Galloway, . and in the 

 counties of Down and Derry, this rock lies directly on granite, 

 — a circumstance which we should at first sight be inclined to 

 consider as indicating its subsequent formation. This thought, 

 however, vanishes the moment we contemplate the veins of 

 granite by which it is traversed. Of these there are many ex- 

 amples ; 



* Since I read this paper, I wrote to a friend at Coniston, requesting a few 

 of these specimens, well characterised, might be sent me : some of which are de- 

 posited, along with the rest, in the cabinet of the Society, (Nos. 64, 65.) 



