284 ON THE GEOLOGY AND 



grauwacke is generally fine grained, of a ligh gray 

 colour ; the fragments, as well as the cement which 

 connects them, appear to belong to quartz ; it is found 

 on the north side of the ridge, in thin beds or layers, 

 directed from the north-east to the south-west, and 

 dipping to the north-west ; this grauwacke is evi- 

 dently of posterior formation to the sienite, and must 

 have been formed, after the surface of this rock had 

 undergone those changes which we at present ob- 

 serve in it ; for instead of presenting a parallel strati- 

 fication, it is found inclining in a diametrically oppo- 

 site direction, and covering the edges or crest* of the 

 layers of sienite, as is observed in fig. 2. plate. 

 The grauwacke and its mode of superposition can 

 be w r ell observed on the road from Franklin to Dr. 

 Fowler's, (the owner of the spot) at about a quarter 

 of a mile below the furnace ; it is covered by a blue 

 limestone, which rests upon it in parallel superposi- 

 tion ; this limestone is found in layers or beds of va- 

 riable thickness ; its colour is a pale gray, sometimes 

 of a deeper gray, passing into blue ; its texture is 

 compact or subsaccaroidal ; near the grauwacke it 

 is slaty ; it contains as well as the grauwacke, fluate 

 of lime, of a pale violet colour, which is found in 

 small cavities in the limestone, and appears to have 

 been formed by infiltrations into it, and the rocks 

 under it ; it cannot, therefore, serve to connect these 

 rocks with the sienite, in the limestone of which, it 



* Outgoings of Jameson. 



