Notes on the Geology oj Murray Bay. 141 



4. Gneiss as before. 



5. Black hornblendic slate with films of mica on the planes of 

 cleavage or bedding. 



On the opposite side of the bay the gneiss rises into the high and 

 rugged promontory of Cape Heu, in which a great thickness of 

 this rock is exposed, presenting a succession of hard angular ridges, 

 and having its strike nearly in the direction of the shore or S. 25° 

 W. (see Fig. 1). Cape Heu rises through Silurian limestones which 

 appear on both sides of it and inland. On the west side after an 

 interval occupied by the Silurian beds, the gneiss reappears with 

 a high dip to the N. W., and containing thick veins of led fel- 

 spar. In tracing it along the shore it becomes nearly horizontal. 



I'leonem t:Hiu 



W Fig. 1. B 



(a) Silurian, (b) Laurentian. 



and then dips to the north, and finally becomes vertical and 

 much contorted. Here it contains a vein or bed of coarse grained 

 granite. Next appear mica and hornblende slates, the former with 

 garnets and having a strike S. 20° W. to S. 30^ W : then after 

 a space of 150 yards without section, white quartz rock 45 feet 

 thick, and in a vertical position, and succeeding this gneiss with 

 bands apparently of crystalline limestone 4 feet, coarse crystalline 

 dolomite and serpentine 10 feet, and gneiss 4 feet ; after which 

 these rocks are concealed by the Silurian beds, resting on them 

 unconformably. 



Westward of Cape Heu the quartz rock again appears, and 

 seems here to overlie the gneiss, and no other beds appear be- 

 tween it and the Silurian rocks, which here appear in great 

 mass, forming the conspicuous clifi* of L'Ecorch^. West of this, 

 and toward Cape Baleine, the shore runs nearly in the junction of 

 the Laurentian and Silurian, the alternate appearance of which at 

 the several points and capes, gives a confused appearance to the 

 coast section, increased by the fact that the Silurian beds are bent 

 into an anticlinal fold near the junction, and that dislocation and 

 denudation have moulded the Laurentian into such irregular 

 forms. Fig. 2 represents a portion of the shore looking east. 

 The Silurian rocks are shaded and appear in the foreground, in a 

 reef dry at low water, and in the cliff of L'Ecorche. The Lauren- 



