of Lake Superior. 229 



layers two feet thick ; the direction being N.W. and the dip N.E. 

 Similar appearances exist near this on the main ; but every where 

 else the rock is massive, or full of confused cross-rents. For the 

 remaining two miles there is an apparent alternation of greenstone 

 and granite (perhaps sienite), the dimensions of each bed being as 

 follows : — A red granite, extending along-shore 750 yards, is fol- 

 lowed for 1000 yards by an intimate commixture, in tortuous veins 

 and masses of all sizes, of pale greenstone and red granite, the 

 union being most perfect at the south end. Tiiis is succeeded for 

 750 yards by light red granite, three times interleaved in the space 

 of 350 yards by masses of greenstone, each, at a rough guess, 50 

 yards broad. Their sides did not appear to be parallel. Their 

 only being visible lengthwise for a few yards leaves me in doubt 

 whether they be strata, veins, or imbedded masses. In the next 

 and last 1000 yards, the r.ocks are red granite with epidote, more 

 or less veined and mixed with greenstone, either largely in seams, 

 or as in the Rock of Le Serpent in Lake Huron, or more minutely 

 still. I have had no opportunity of ascertaining correctly the 

 ingredients of the rock I here call granite. They are all unstra- 

 tified, except where that structure has been adverted to above. 



The very short beaches under Gros Cap, and the larger of 

 Batchewin Bay, are plentifully lined with bowlders of white sand- 

 stone, amygdaloids, greenstone, the Gros Cap porphyry, and a 

 greenstone porphyry, abounding chieily in Lake Huron. To these 

 are to be added the greenstone puddingstone of Pelletan's Channel, 

 (L. H.) the jasper puddingstone of the foot of Lake George, and 

 various quartzes, granites, and gneiss. 



The Falls of St. Mary, (and that river generally, it may be 

 concluded,) Batchewine Bay, the Maple Islands, Green Island, 

 and the two bays south-east of Point Marmoaze, are based on 

 sandstone ; in an horizontal position, universally, on the east 

 and north shores, except near the north headland of Gros Cap, 

 where, for a short distance along the margin of the water, it 

 inclines from the hills ; by displacement, not conformably to the 

 elder rocks, for here they seem to be massive. This sandstone 

 has been shewn to be of vast extent in Lake Superior. It is 



