various parti of Scotland. 435 



with the theory of the aqueous formation : but the objection on this 

 ground has been urged before. In one a crystal of schorl passes 

 through the centre of a garnet, and the whole is suspended (if I may 

 use such a phrase) in the quartz. In others the crystals of schorl 

 are simply suspended in the quartz or felspar, and have perfect 

 termjnations. It is evident in the first, and strongest case, that the 

 schorl crystals must have been supported in a fluid of equal gravity, 

 possessing no action chemical or mechanical on it, while a garnet 

 was allowed to crystallize round it, and that this extraordinary state 

 of things must have continued during the time which it would 

 require to deposit a mass of quartz from a watery solution around 

 the whole, a period, which if we may judge from the slow formation 

 of chalcedonies from water, involves a supposition little short of 

 miraculous. 



Such are the difficulties which beset this very simple and probably 

 very common occurrence. I do not mean by adducing it, to say, 

 that no theory is worthy of attention which cannot explain all the 

 phenomena. My wish is rather to excite the industry of those 

 who cultivate geology, to the investigation of the still recondite 

 chemical actions, from which alone we can hope for the solution 

 of these and numerous other difficulties which attend us. 



hoch Laggafi. 



I am merely desirous of pointing out under this title a bed of 

 limestone, lying in a country so little visited, that it has not yet 

 been observed by mineralogists, and of sufficiently rare occur- 

 rence to render it an object of notice. 



The whole country about Loch Laggan is of that composition 

 which forms the far larger part of the highland districts, namely 

 micaceous schistus. 3 i 2 



