198 ON THE GEOLOGY AND PETROGRAPHY OF BATHURST, N.S.VV,, 



probability, suffering from la maladie du granite so noticeable 

 now.* 



A glance at section i, PI. xvi. will show some of the various posi- 

 tions of the river from its oldest bed to its present course. The 

 remnants of old channels on the slopes between the river and the 

 Bald Hills vary in age. The oldest drift we know to be Pliocene. 

 The newest is now forming, and the most we can do is to point 

 out that the drifts cover intervals from the Pliocene to this day. 



ix. Igneous Rocks. 



Granite — In the field. — There is no lack of outcrops of granite, 

 even within the limits of the sketch map appended. Wherever 

 the granites show on the surface they are decomposed. This is so 

 constant a character that it may be taken for granted that the 

 whole surface of the granite is undergoing rapid decomposition, as 

 stated in a former part of this paper. In sinking wells, ten and 

 twenty feet of decomposed rock are frequently met with. All 

 along the river valley wherever the rock crops out it is invariably 

 decomposed. Indeed, Bathurst affords a good instance of the 

 sickening of granite referred to by Dolomieu. Even when the 

 minerals of the rock hold firmly together, their slices, cut from 

 surface specimens, show cloudy felspars and incipient kaolin ization. 

 For microscopical purposes the best locality to procure chips for 

 micro-slices is at the waterworks, where a deep shaft has been 

 put down, and among the broken boulders on the northern slopes 

 of Mt. Pleasant. 



Granite is exposed up the river to O'Connell's Plains, and along 

 the railway line to Locksley. Between Locksley and Brewongle 

 some interesting junctions may be noted, one in particular at a 

 bridge crossing the line between the two stations. Following the 



* The disintegration of granite is a striking feature of large districts in 

 Auvergne, especially in the neighbourhood of Clermont. This decay was 

 called by Dolomieu "la maladie du granite." The phenomenon may, without 

 doubt, be ascribed to the continual disengagement of carbonic acid gas from 

 numerous fissures. Lyell's Principles of Geology, 11th edition, Vol. I. p. 409. 



