GEOLOGY OF THE VICINITY OF LITTLE FALLS 79 



where there was in all likelihood a minor divide, located by the 

 more resistant rocks domed up there. This col must also have 

 been cut down in glacial times and quite probably by glacial 

 erosion at a time when the full current of ice swept over the 

 Adirondacks. Though constricted, the valley is not a gorge at 

 Middleville, is U-shaped, there is neither fall nor rapid in the 

 stream, and the knobs of pre-Cambrian rock near the creek level 

 show unmistakable evidence of glacial wear. Just above Middle- 

 ville, too, the valley is heavily clogged with drift to below the 

 €reek level, and even immediately below the town, where the val- 

 ley is narrowest, till descends in places to the stream level. 



East Canada creek also, so far as it lies within the map limits, 

 is not in its old valley, though where that was can only be con- 

 jectured. From Dolgeville to the fault line it is in a wholly post- 

 glacial valley, with rapids, and a high fall with a gorge below. 

 Below the fault the stream enters the east side of a preglacial 

 valley, which lies to the west of its present course, and out of 

 which it turns into the modern gorge above Ingham Mills. For a 

 mile below Ingham it apparently crosses another preglacial valley, 

 nothing but drift showing in the banks and bed, and begins to dis 

 close rock again in the bed just before leaving the sheet, beyond 

 which it has cut another rock gorge. 



North of Dolgeville the stream is in a preglacial valley, out of 

 which it turns at the big bend to the east [see pi. 15, and 

 compare with pi. 6, 7, 8, 9]. To the northward along this 

 line there is heavy drift, with no rock showing, for some miles; 

 and on the prolongation of the same line to the south no rock 

 -exposures occur over a belt at least a mile in width, all the way 

 to the Mohawk. The course of a preglacial valley, rather closely 

 following the Little Falls fault line and lying between that and 

 the present valley of East Canada creek, is thus rendered prob- 

 able, and such a valley would also seem likely on structural 

 grounds, adjusted to the belt of weak Utica shales between the 

 Little Falls and Dolgeville faults. 



The smaller tributary creeks all show the same general features ; 

 here they develop rapids, falls and gorges; above and below they 

 show nothing but heavy drift in banks nnd bed. Their present 



