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^Grenville Kmestene orotiier 

 rela+wely weak rock. 



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 I I I S/enitfe 



SCALE 



Grenville gneisses - 

 d 1 st I n ctl y St rai if 1' e d 



600 FT. 



East-west structure sections through the western side of Chimney mountain 

 (looking northward) 



Fig. I Showing essentially the condition of things not long before the 

 development of the great rift. The position of a prominent joint plane is 

 indicated in the Grenville gneisses. 



Fig. 2 Showing essentially the condition of things immediately after the 

 development of the great rift due to breaking away of a large block from 

 the parent ledge of Grenville gneisses. 



Fig. 3 Showing the present condition after some weathering and the ac- 

 cumulation of large, angular rock fragments at the bases of the steep slopes. 



