CANTY-BAY. 



237 



a wedge. The tuff continues onward around the 

 coast to Canty Bay, forming cliffs of considerable 

 magnitude. At Canty Bay, the tuff alternates 

 with basaltic greenstone, and is traversed by veins 

 of green and red coloured tuff. The tuff is to be 

 observed gradually passing into a red sandstone, 

 which alternates with white sandstone. This sand- 

 stone exhibits much variety in structure ; alternates 

 with beds of red and green coloured clay ; and is 

 traversed, in some places, by veins of amygdaloid. 



The sandstone at Canty Bay, and along the coast, 

 for some distance, varies, not only in colour, but also 

 in structure. In some places it is reddish brown ; 

 in others, yellowish or greyish white, or of a moun- 

 tain-green colour. Quartz is the predominating 

 constituent part ; and felspar and mica are occasion- 

 ally intermixed with it. The basis, or cementing 

 material, is clay, or calcareous marl, or the quartzy 

 particles are immediately joined together, without 

 any perceptible basis. Frequently, beautiful circu- 

 lar spots are to be observed in the sandstone. These 

 are either of green coloured clay, or of particles of 

 felspar and quartz joined together, without a basis, 

 thus forming a variety of granitic rock *. They vary 



* Masses of this description, when they appear in the 

 great scale, form mountain masses or hills of granite in sand- 

 stone. In the primitive slaty rocks, as gneiss and mica- 

 slate, there is a series of the same description, formed by im- 

 bedded cotemporaneous masses of granite, varying from the 

 size of a nut to several fathoms or miles in extent. 



