LAKE OF THE WOODS.—LAURENTIAN. ya 

epidote. A small island off Windy Point is of gneiss, with a strike of 
N. 51° W. and a high dip to the south. 
49. Making a traverse of three miles to Bick Island—which lies to 
the north, and is the most southern island of the chain which 
stretches across the eastern bay of Sand-hill Lake—the rock is found to 
be a granitoid gneiss with a strike of N. 70° W. It probably belongs to 
a stratum considerably underlying the last described beds, on the main- 
land. The south-eastern point of the island shows grey and hornblendic 
gneiss striking N.50° W. The eastern point is formed of grey granitoid 
gneiss, only showing in a few places sufficient traces of stratification 
to allow the strike—which is N. 65° W.—to be observed. In several 
places in this vicinity there are large irregular segregation veins com- 
posed of red orthoclase felspar and white quartz. The felspar crystals, 
have as usual, formed first, and their crystallization is very bold; one 
of them beautifully cut and polished in section by glacial action, measuring 
seventeen inches in length. The quartz has filled irregular pockets 
remaining among the felspar crystals. Two miles north, and still on the 
same island, a point was observed where granitoid gneiss of the usual 
type, reddish-grey in colour, and also holding veins of felspar, was cut by 
a large dyke of very compact dark-green diorite. The northern portion 
of this island is entirely composed of grey granitoid gneiss, in some places 
scarcely distinguishable from granite, and of which the strike and dip is 
indeterminate. At the extreme northern point, it forms low ‘gently 
rounded knolls which rise slightly above the surface of the drift. 
50. Middle Island, opposite the north end of Bigsby Island and for 
about two miles northward, is composed of thinly bedded and often 
ribbon-like gneiss and mica schist, with some greenish layers like those 
intercalated in the strata last described on the mainland. The attitudes 
at three points, beginning at that furthest south, were found to be respec- 
tively: dip N. 53° HE. < 68°—S. 60° W. < 35°—S. 65° W. < 38°— 
indicating a well marked synclinal fold. The beds where they dip 
north-eastward on the south side of this synclinal, are probably the 
return of those last seen on the mainland, and must overlie the granitoid 
gneiss of Bigsby Island. It can hardly be supposed, however, that the 
phenomenon is a simple anticlinal in which all the beds from Windy 
Point to this locality are included, as the distance is at least eight miles, 
and the angles of inclination high. It is more probable that a series of 
sharp flexures having an approximate east and west direction, are super- 
imposed on a long gentle swell of the strata parallel to them, and 

