Hi EXPEDITION TO THE 



composed of granite; in this case the feldspar is of a red- 

 dish appearance, and imparts to the granite the colour from 

 which the name of the island was derived. We have fre- 

 quently observed in the islands which we visited that the 

 north-eastern extremity was bounded with boulders, the 

 average diameter of which might be about two feet. 

 Though these sometimes extend all round the island, still 

 it is more usual to observe them only at the north-eastern 

 point, seeming to indicate that they were carried down 

 from that quarter. The direction of the strata of mica-slate 

 appears to vary from north 60° to north 80° east. The 

 angle with the horizon varies from 65° or 70° to the per- 

 pendicular. The rock is penetrated in some places with 

 iron pyrites ; veins of quartz also appear occasionally 

 through the mass. We saw no limestone, but Dr. Bigsby 

 informed us that he had observed some on the shore of the 

 lake. It is probable that we had in sight during our course 

 through the lake, at least 200 islands, whence an idea may 

 be formed of the immense number which it includes. 

 Towards the south-east there is a space without islands, 

 and this gives rise to what is termed the " Grand traverse," 

 which is, however, only ten miles long. From the number 

 of islands, when a slight wind blows upon the lake, it soon 

 raises a high but short wave, which is very dangerous to 

 bark canoes ; hence the least wind Will sometimes occasion a 

 considerable delay in the journey. Desmarais was once 

 encamped eleven days without being able to cross those 

 ten miles ; and he has heard of canoes being detained on 

 the adjoining islands for twenty-two days. We were for- 

 tunate, as the wind which had blown the preceding day had 

 lulled, and we passed the traverse without difficulty. We 

 met in it a canoe with three men who were coming from 

 Rainy lake ; they had been detained twenty-four hours by 

 the wind. 



