384 MINERALOGIGAL OBSERVATIONS 



7. About 400 yards farther down the lake, to 

 the N. W. of the castle, at a sort of knoll, called 

 Millgoan, I found the same appearances as at the 

 former place. Compact gneiss running N. and S. 

 with the granite mixed in it as before. I could 

 not here determine the dip of the strata. I think 

 they are nearly vertical, as they appear all to be 

 about this place. 



In the granite of this district, I notided a phe- 

 nomenon, which I had little opportunity of seeing 

 in the Dee district. There, indeed, I had ob- 

 served it in a few instances, and on a very small 

 scale ; but here it is common, and its features 

 prominent. I allude to fragments of compact 

 gneiss occurring in the granite. I observed one 

 of these fragments of a tabular shape, two feet 

 long, about ten inches broad, and four thick. Some 

 of them have disintegrated more rapidly than the 

 granite in which they appear imbedded, and so 

 have left hollows in it, and have indeed fallen out. 

 Others of them have weathered more slowly than 

 the surrounding granite, and are seen projecting 

 from its surface. I could not observe any instance 

 of this rock (the compact gneiss) either in the 

 ' strata or the fragments alluded to, passing into 

 the granite, unless the manner in which this rock 

 and the granite unite, be called so, which is in as 

 distinct, but at the same time intimate a manner, 

 as the alburnum or white wood of the oak, unites 

 with the real or red wood. The termination of 



