350 15LA, GEOLOGY. 



The conglomerate at Lossit hill possesses a more de- 

 cided character. It is found distinctly placed above 

 the white limestone just described, and in many places 

 in contact with it ; forming a considerable, and apparently 

 a single bed. This bed has that air of antiquity which 

 characterizes the older rocks, having an appearance of 

 distinct stratification, but being at the same time divided 

 vertically into irregular prismatic forms, resembling at 

 a distance, some kinds of granite. Its basis is a coarse 

 schist, and it splits naturally into thick schistose laminae. 

 It contains fragments, scarcely rounded, of granite, and 

 of the white limestone on which it lies ; these varying in 

 dimensions from a tenth of an inch to that of several 

 inches. By this last character, as well as by its position, 

 its posteriority to the limestone is determined. It is pro- 

 bably a portion of the conglomerate described before, the 

 variation depending merely on the character of the subja- 

 cent rock; a conjecture strengthened by a circumstance 

 that will be immediately mentioned. The character and 

 position of the conglomerates of this description, bespeak 

 an antiquity commensurate with that of the schists which 

 they accompany. They are rare, as far as I have observed, 

 in Scotland ; but besides that described in Garveloch, and 

 that occurring in Schihallien, they are found in the hills 

 which extend from this mountain to Ben vualach; as 

 well as at the source of the Spey. There is nothing how- 

 ever in this appearance inconsistent with general facts, 

 but there is rather, on the contrary, ground for surprise, 

 that such rocks do not more commonly occur ; since the 

 several schists which they accompany have been formed 

 from fragments of the same rocks more comminuted. 

 Analogous conglomerates seem to be most common in 

 the quartz rock, as will appear from the preceding descrip- 

 tions of Jura, Scarba and Lunga $ and they are found alter- 

 nating with the strata of finer texture that are composed 

 of the same materials. The reason of this will perhaps 



