28 Z. V. Pirsson — Crustal Warping in the 



bed below the outlet : " Very little rock in situ can now be 

 seen, altliouji-h it is evident from the topoo-raphy tliat the detri- 

 tus was de])osited in a pre-existing shallow narrows." Even 

 were it admitted that the valley was dammed with glacial drift 

 to a depth of 500 feet at this ))oint, there would still be a rock 

 barrier at the Mountain Rapids at the foot of the next stretch 

 of still water, known as Seven League Lake, whose surface is 

 about 50 feet lower than that of tlie main lake above, and 

 which discharges down a j-apids obstructed by rocky reefs and 

 islets. Thus, even if a morainal dam exists of the great depth 

 postulated, it can only be regarded as a secondary affair, form- 

 ing a sort of facing on tlie downward slope toward the lake 

 center of the bed-rock barrier beneath and giving at the most 

 a height of some extra 50 feet to the lake.' ' 



It is not intended, of course, to deny in this tliat morainal 

 deposits may not lie on the floor of the old canyon. The}' 

 probably do, and the real rock floor may lie considerably 

 deeper than the present bottom of the lake. At old Fort 

 Narrows (B, on map) the gorge in large part is tilled with a 

 glacial deposit nearly choking the pre-existing narrows at 

 this point. This very probably represents material accumu- 

 lated by the local southeastward sub-glacial current in the ice 

 which would be checked at this point. Only, as Barlow re- 

 marks, it could not have been originally much greater than it 

 is now since on the down-stream side it slopes off with great 

 sharpness to the depths of the lake. If it once projected some- 

 what above the present lake surface it was rapidly cut away 

 until a grade was established between the two parts of the 

 lake, and since then no great change in it has occurred. 



The first two hypotheses of lake origin having been consid- 

 ered and dismissed there remains the third, audit now seems 

 fairly evident that the lake represents a pre-glacial canyon 

 which, by down-warping in its middle part, has become flooded. 

 The total amount of down warp may be roughly estimated to 

 be as much as 500 feet in the center of a distance of 50 miles in 

 a general north to northwest and south to southeast direction. 



Lalce Kipiioa. — If such down-warping has occurred, it can 

 scarcely be supposed that the immediate region would not be 

 affected by it and the other drainages and lakes should show 

 evidences of it. While not enough is known of those geologic 

 features of the area which would offer decisive evidence on 

 this point, there are some facts which appear to favor it. Thus 

 Lake Kipiwa is so near to Lake Temiskaming and parallels 

 it for such a distance that it should also be affected. It has 

 not been seen by the writer, but Barlow describes it as filling 

 several valleys parallel in a general way to Lake Temiskaming. 

 These, like Temiskaming, cut across the general direction of 



