RAINY LAKE AND LAKE OF THE WOODS. 



277 



selves not far from the entrance of Lac La Croix. The 

 direction of the longest axis is 1ST. 60° W. A line pro- 

 longed through the granitic islands, in a JST.W. direction, 

 touches the schists about three hundred yards further on. 



Their apparent dip, as seen from the lake, was JST.W., 

 at an angle of about 45°. One island, wholly composed 

 of schist, inclined at a high angle, is followed at a distance 

 of about fifty yards by a long flat gneissoid dome. About 

 six hundred yards from the island, the schists clip lightly 

 to the S.E. On the north side, the dip could not be seen ; 

 but on the west side they were observed to bend round in 

 a curved form, and from a N.W- dip towards the S.E. On 

 the next island, the gneiss was intersected by numerous 

 joints having a direction N. 70° E., and by quartz and fel- 

 spathic veins, bearing N. 25° W., or nearly perpendicular 

 to the former. Its surface towards the N.W. by W. was 

 smooth, and inclined at an angle of about 10°. The rock 

 of the Nu Portage is a granite containing mica in plates, 

 and everywhere dotted with numerous beautiful specimens 

 of plumose mica. 



Dr. Bigsby thus sums up the geological conditions of 

 Eainy Lake where a change in the direction of the strike 

 is very decided. 



" Chloride and greenstone slates, gneiss and mica slate, 

 in proportional quantities in the order here set down, 

 seem once to have occupied the lake basin, with an 

 E.N.E. strike, and a M.W. dip at a high angle usually ; 

 but subsequently a very extensive outburst of granite, 

 with some syenite, has taken place to the great distur- 

 bance of the stratified rocks, and penetrating them both 

 in intercalations and crosswise ; these intrusive rocks 

 occupy a very large portion of the lake." 



He divides the region of Eainy Lake for convenience 



