54 The he-currents of Minnesota Upham. 



the surface, yellow) till overlyinj> the red till in this district, and 

 more complete discussion of the glacial period, its ice-sheets, and 

 their various drift deposits in this state, have been partially pre- 

 sented in the fifth, sixth, eighth and ninth annual reports of the 

 Geological and Natural History Survey of Minnesota, jind will be 

 fully exhibited in the final reports of this survey. 



In the later part of the last glacial epoch, the ice Howing from 

 the northeast formed a terminal moraine of very roughly, knolly 

 and hilly till, which is intersected twice by the Mississippi river on 

 the northern border of Dakota county, once seven to ten miles 

 below St. Paul, and again between St. Paul and Fort Snelling. 

 This moraine is crosseil by the river-road below St. Paul in 

 sections 11, 14 and 22, Inver Grove. Thence it extends to the 

 west a few miles, and soon (at the east side of Wescott station^ 

 curves to the north, forming the belt of irregularly broken high- 

 land, com])osed at the surface of till with many boulders, which 

 occupies the northwest part of Inver Grove and the w^est half of 

 West St. Paul, varying from two to three miles in width, and 

 elevated about 30p feet above the Mississippi, or approximately 

 1 ,000 feet above the sea. The heights of the separate hills or 

 ridges or this belt are from 40 to 75 feet above the hollows. In 

 Mendota another belt of morainic drift-hills, also accumulated by 

 the ice-current from the northeast, probably at nearly the same 

 date with the preceding, lies one to three miles farther west, form- 

 ing prominent hills and ridges in sections 35, 34, 20. and the 

 southeast part of 23, about 250 feet above the Mississippi, and 50 to 

 75 feet above the belt of smooth prairie a mile wide between this and 

 the parallel line of hills in West St. Paul. The most conspicuous 

 hill of this moraine in Mendota is Pilot knob, in the northwest 

 quarter of section 34, only about a mile southeast from Fort Snel- 

 ling. Its height is 260 feet, approximately, above the Minnesota 

 and Mississippi rivers. The continuation of this moraine to the 

 north lies east of the Mississippi, reaching from the high hills in 

 Reserve township two or three miles northeast of Fort Snelling, 

 to the belt of hills, composed at the surface of very knolly drift, 

 chiefly till, but partly gravel and sand, that lies about one mile 

 east and northeast of the borders of Minneapolis, having a height 

 75 to 150 feet, and a few miles farther north fully 200 feet, above 

 the plain of modified drift on which this city is built. 



At this time the ice-current from the west appears to have 



