REPORT OF THE DIRECTOR AND STATE GEOLOGIST 1902 r39 



long in life, with great erosive power. Perhaps they not only 

 denuded the Archean rocks at Little Falls, but cut these down 

 to the terraces under 500 feet. Then the Iromohawk used the 

 remaining drift in the valley as an abrasive to rasp down the rock 

 barrier to near its present condition; cutting away the valley 

 deposits of the earlier stage and grading its channel to the 

 falling outlet. 



The above writing assumes a fair permanence of relative levels 

 throughout the whole area under discussion, or that the whole 

 upper Mohawk valley has been equally lifted by the Postglacial 

 continental uplift with no evident deformation. 



THEORETIC LEVELS IN THE ORISKANY AND SAUQUOIT VALLEYS 



In this chapter it is proposed to indicate in a broad way the 

 stream and lake phenomena which should, according to our 

 theory, be found in the connected valleys. This will enable 

 the student of the subject to follow out the matter with more 

 detail and system, and to verify the theoretic history. 



1 Mohawk gradation plains. The writer supposes that both 

 the Oriskany and Sauquoit creeks are now graded to the Mo- 

 hawk river as their base level. The Sauquoit, being the smaller 

 stream, should have the steeper gradient. Artificial damming 

 of the streams has interfered with the uniform current and 

 grade, but the natural flood plains can generally be determined. 



2 Old plains correlating with Iromohawk as base level. By 

 taking the present flood plain of either stream as a datum 

 plane, the ancient flood plain which the stream formerly built 

 when it was adjusted to the Iromohawk river as its base level, 

 may be found some 20 feet higher. Such plains of the older stage 

 in the stream history may be recognized in the level stretches of 

 alluvium, decidedly above the possible reach of the present stream. 



It must be recognized that the actual hight of these parallel 

 planes will rise as we proceed up the stream valley. 



3 Delta plains of the Utica lake. Through the area of lower 

 ground, north and northeast of Clinton and north of New Hart- 

 ford, will be found level stretches of gravel or sand at altitudes 

 of 520 to perhaps 550 feet. These represent the stream accumu- 

 lations in the waters of the " Utica lake." They will have some 



