I82f MINERALOGY OF THE PENTLAND HILLS. 



of the North Esk river, which occurs in this 

 group, extends from Cock Rig, where the sources 

 of the river are situated, to Caerlips Bridge, where 

 the Esk flows into the low country. It is narrow, 

 and is bounded on both sides by green hills of con- 

 siderable height : these are Caerlips Hill, Mount 

 Hill, and Cock Rig on the one side, and Spittal 

 Hill on the other. 



Section U. 



The rocks of which this portion of the Pent-* 

 land Hills is composed, belong to the Transition, 

 rioetz, and Alluvial classes j no fixed rocks of the 

 Primitive class, as far as I know, having hitherto 

 been discovered in any part of the group. The 

 Floetz rocks, v/hich are by much the most abun- 

 dant, form the highest, and sometimes also the 

 lowest parts of the group ; whereas the Transition 

 rocks in general occur low down ; and both sets 

 of rocks are more or less covered with Alluvial 

 substances. 



We shall now describe these rocks in the order 

 of their relative antiquity, beginning with the 

 transition, which are considered as having been 

 deposited before the floetz and alluvial rocks, and 

 lie deeper in the crust of the earth. 



