24 GUIDEBOOK OF THE WESTERN UNITED STATES. 
on in this region, and the country is covered with a dense growth of 
scrub oak. 
For some distance beyond Randall the country consists largely of 
Swamps and scrub-oak uplands, but north of Cushing the surface 
becomes rougher, consisting of knoblike hills with 
swamps or lakes between them. When seen from 
some commanding eminence the country appears to 
be a maze of more or less regular conical hills among 
which the railway turns and twists to find a level path- 
way. As the traveler proceeds he will note that the depressions be- 
tween the hills become more pronounced, and when he is within a mile 
of Lincoln, or at milepost 126, he can see on his right one of the largest 
depressions i in the region, eobapied by Lake Alexander. Evidently 
the character of the submerged surface is much the same as that 
around the lake, for the surface of the lake, although extensive, is 
broken by morainic islands that add greatly to the charm of the scene. 
The rough topography reaches its culmination near Lincoln, where 
the hills range in height from 100 to 150 feet and are very steep. As 
described in the footnote on pages 26-30, the morainic 
material forming these hills was brought by a great 
glacier (the middle ice sheet) that pushed into this 
region from the northeast. It extended only a little 
beyond Mississippi River, and the rough topography about Lincoln 
is due to the deposition of a part of its terminal moraine. 
Lincoln is mainly a summer resort and is an attractive place for 
those who enjoy boating and other aquatic sports. The wooded 
Cushing, 
Elevation 1,288 feet, 
Population 313.* 
St. Paul 123 miles. 
Lincoln. 
Elevation 1,304 feet. 
St. Paul 129 miles, 
are thin layers of slate and paint rock, the 
paint rock usually resulting from the 
alteration of the slate. 
At the east end of the range, near Birch 
in consequence 
of the intrusion of granite to the north and 
of gabbro to the south. As a result con- 
siderable amphibole has been developed 
in the ferruginous rocks, magnetite has 
segregated into layers, and the rocks have 
become hardened. 
Thin beds of conglomerate and shale 
— The basal beds of the Creta- 
us | y carry detrital iron ore de- 
rive from the weathered Biwabik forma- 
prea portions of the Biwabik 
formation are rich enough to constitute 
iron ore. These occur in isolated masses 
along the eroded surface of the formation 
and are generally not over 200 feet thick, 
although some are thicker. The work- 
ba Pe - J 4 id 
due to the action of surface waters, which 
have leached out the silica and some 
other elements and have left the iron in 
a more highly concentrated form. Con- 
centration of this nature, in places to 
which water solutions have found more 
of — pebbles. 
The geologic conditions in the Cuyuna 
range appear to be sn identical with 
those in the Mesabi range, described 
above, but as the Sivan range has been 
only slightly developed its geology can 
not yet be described in detail. 
