28 GUIDEBOOK OF THE WESTERN UNITED STATES. 
shores offer many inducements to the sportsman or to the summer 
visitor who is in search of relaxation from the breathless hurry of 
modern city life. 
The plain extends along the railway to a point 4 miles northwest 
of Perham, where it gives place to rough, hummocky land that 
marks an eastern point of the great morainic ridge on the west of 
the track. When this moraine was formed the ice had disappeared 
from the country to the east but covered all that part of the State 
lying to the west. 
From Luce to Frazee the ground is generally 
swampy or dotted by small lakes or ponds. 
At milepost 196 the railway crosses Otter Tail River, here flowing 
to the east. 
On account of the numerous ridges this stream wanders 
about from lake to lake, finding an outlet by an exceedingly round- 
about course. 
Only a fow of these lakes are visible from the train, 
(western ice sheet) which came from 
central Canada. The eastern part as far 
south as the vicinity of St. Paul was 
covered by ice (middle ice sheet) from 
the region south of Hudson Bay, and a 
small area on the border of the Lake 
Superior basin was covered by ice (Supe- 
rior ice sheet) which came in from the 
ugh that basin. The western 
sheet brought in fragments of limestone 
and shale, the middle sheet carried south- 
ward much material from the iron ranges 
and also red sandstone from the west end 
of Lake Superior, and the eastern or 
Superior sheet transported to the limits 
of its advance large amounts of the red 
sandstone bordering that basin 
The effect of these invasions was to fill 
up and obliterate the valleys or to block 
posi 
of the border of each of the ice sheets. 
Sand and gravel were spread out 
termed outwash aprons. In places where 
the ice border melted back rapidly no 
moraines were formed, but i 
nearly level surface, composed of epider 
clay or till. 
The moraines of the Superior sheet en- 
circle the west end of the Lake Superior 
basin ina series of concentric ridges, each 
| ing later tha one without 
& 
formed by the western icé sheet lie in 
the high country along the valleys of 
Red River and Minnesota River. These 
streams are bordered by broad plains 
which owe their form to the fact that 
they lay under the deep part of the ice 
sheet and along its axis of movement. 
The moraines of the middle ice sheet 
are well developed south and east of St. 
Paul and in central Minnesota. The 
Northern Pacific Railway traverses one of 
the most prominent moraines of this ice 
sheet, between Little Falls and Staples. 
The three advances of ice, though oc- 
curring in a single glacial stage, did not 
take place at the same time. After the 
middle sheet reached its maximum and 
melted back nearly if not quite to the 
Canadian line, 1 the; okher shoots sini te: 
ere 
aneeean its drift with their decane 
The western ice in places extended 75 
miles or more into the district the middle 
sheet had abandoned. 
The map on sheet 3 (p. 32) is intended 
to show the toni pr invasions of 
Minnesota durin, nsin stage, 
but as the three fete did not invade 
brought in later by the western sheet its 
limit on the west can be only conjectured 
but it probably covered much of the 
northern part of the State. 
