The Kcweenazvan iti Minnesota. — Elftinan. 97 
mediately south of the Itasca moraine the upper till layer is 
of northeastern origin. Between the Itasca and Mesabi mo- 
raines the till is largely covered by modified deposits and 
is usually not more than twenty feet thick. In T. 60 N., R. 
9W., however, it attains a thickness of more than fifty feet. 
North of the Mesabi moraine the till is scarce and when pres- 
ent is represented chiefly by boulders. 
MODIFIED DRIFT. 
The modified drift consists of the stratified gravel, sand and 
clay deposited by streams flowing from the retreating ice. 
Kames, eskers, plateaus, river deltas and valley drift repre- 
sent it. 
Kames are of common occurrence and are associated with 
all the moraines. They are especially well developed along 
the Highland and Itasca moraines and their eastern extension, 
the Itasca-Highland moraines. In the Mesabi moraine, be- 
tween Hungry Jack lake and the international boundary, are 
also well formed kames, one of which is traversed for one- 
eighth of a mile by the portage from Rose to Rove lake. Both 
of the moraines northwest of Marks township in Ontario 
show a strong development of kames and kettle holes. 
Eskers were observed only in a few places. The most 
prominent one is in T. 62N.,R. i W., one to two miles west 
of Devil Track lake. This is a narrow ridge over a mile long 
and fifty feet high, above the land on either side. It is com- 
posed of fine gravel and sand, with a few large boulders. In 
this vicinity are also numerous kames, which occur near the 
northern edge of the Itasca-Highland moraine. 
Plateaus of sand and gravel similar to the kames in struc- 
ture form isolated hills rising as high as 150 feet above the 
surrounding area. The most conspicuous plateaus occur 
immediately south of White Iron lake in T. 62N.,R. 12 W.; 
at the northeast end of Gabbro lake, T. 62 N., R. 10 VV.: aiul 
at a number of localities several miles north of the Mesabi 
moraine. These plateaus are especially noticeable silice they 
lie at some distance from the moraine. 
River deltas occur most abundantly south of the Highland 
moraine. They were formed in connection with lake Duluth. 
The most prominent ones observed by the writer occur from 
