S82 MINERALOGICAL OBSERVATIONS 



or tunnel driven through the rock, over which its 

 waters were discharged at the northern extremity, 

 took nineteen feet from its depth. The object 

 was to gain ground on its banks. But though 

 many acres of surface, have in this way been 

 obtained, they are in general but of little value, 

 being mostly barren sand or gravel, or rolled 

 pieces of rock of considerable size. The rock 

 through which the above-mentioned cut or tunnel 

 is made, is grey-wacke ; and hence issues the 

 " Bonny Doon," whose banks and braes" have 

 been rendered classic by the immortal lays pf our 

 Scottish Bard. 



1 . On proceeding, as I already mentioned, along 

 with Mr Macmillan from his place at Brock- 

 loch, distant from Loch Doon Castle four miles to 

 the east, we came upon the junction of the granite 

 with the stratified rock on the western face of the 

 hill of Knockour, about a mile to the east of Loch 

 Doon Castle. The stratified rock here, in con- 

 tact with the granite, is the same as I uniformly 

 found in contact with it in the Dee district, (ex- 

 cept in one place), and is fine-grained or compact 

 gneiss. The strata are vertical, and the direction 

 is N, and S. Where we made this observation, 

 the ends of the strata run flush on the granite. 



2. My next observation, was on the banks of 

 the lake, still on the east side of it, not far from 

 opposite the castle. Here is conipact gneiss ver- 



