48 BULLETIN OF THE NATURAL HISTORY SOCIETY. 



More complex agencies have been at work in produc- 

 ing the unduLating shore lines at and opposite Indian- 

 town, chiefly the denudation of rocks of nnequal hardness, 

 and the movement of rocks along fault lines. The bold 

 hill at Pleasant point is a mass of granite which has 

 fault lines and softer beds on the south, and softer strata 

 also on the north, and to these owes its prominence; 

 and the deep indentation of Marble cove is clearly due to 

 the softer limestones and slates which lie between the 

 harder quartzites on the south, and the granite, quartz- 

 diorite and gabbro of Indiantown itself. 



In the iSTarrows above Indiantown the rocks are of so 

 uniform a texture that denudation cannot have been the 

 chief agent in producing this somewhat tortuous passage. 

 We shall have to appeal to cross-faults here for an ex- 

 planation of the inception of this passage, though subse- 

 (pient wear by water-action no doubt enlarged and 

 deepened it. 



The formation of caves and subterraenan water 

 courses in the limestone beds in distant ages, (as suggested 

 further on) are also probably in part responsiT)le for the 

 0})ening up of this passage. 



Enlargement of the valleys by deformation op the Earth's 



Crust. 



The occurrence of these faults leads us to speak of 

 the enlargement of the valleys above the ISTarrows, to 

 which we have already referred, as being due to profound 

 faults produced in Huronian and post-Cambrian time in 

 the earth's crust. We may now take a step onward in 

 time and look at this region at the close of the Devonian 

 period. 



Important physical changes had taken place ; the 

 comparatively peaceful condition of the region in the 

 Cambrian ages had been followed by volcanic disturb- 



