(JENOZOIC TIME — QUATERNARY. 



973 



The accompanying birdseye view (Fig. 1551), from a paper by Gilbert, 

 shows the river between Lake Erie to the south and the laud below the 

 Queenston Heights (Q H). To the right is seen the course of the old now 

 drift-filled channel, first recognized by Lyell. The work of excavation is 

 still going on, and chiefly at Niagara Falls. 



The Mississippi Eiver was similarly blocked near its junction with the 

 Minnesota for a distance of about 10 miles, as described by IST. H. Winchell. 

 In the new valley, since made by the Mississippi, St. Anthony's Falls occur. 

 The river is still working at the removal of the falls so as to make the 

 cut complete. 



1551. 



Birdseye view of the Niagara Gorge. W, Whirlpool ; Q, Queenston ; Q H, Queenston Heights ; O Ch, old 



channel. From Gilbert. 



Eock Eiver, in northwestern Illinois, is stated by Chamberlin and Lever- 

 ett to have been a tributary to the Illinois before the deposition of the 

 Kettle moraine. But, through the drift-deposits then made, it was filled up 

 for part of its course and thus was set to work making its present south- 

 westward channel to the Mississippi. 



During this time of melting, fluvial work was going on over all parts of 

 the continent — quiet waters and those of prolonged floods alternating, where 

 ■within the influence of the glaciers. The height of much of the land may 

 still have favored the work of erosion along many valleys. 



The Mississippi was the greater Mississippi through the larger part of 

 the time ; for there is yet no proof that before the ice left the United States 

 it had lost its Winnipeg and Saskatchewan source. The valley received 

 new deposits of loess and silt along some still- water portions, part of it over 

 the earlier Lafayette formation, and silt and coarser beds elsewhere. The 

 rivers of tlie Atlantic border south of New York were adding to the deposi- 

 tions in their valleys and along the seashore. But since snows were less 



