STRUCTURE OF THE ESKER 411 



Through its second mile Birds Hill, or ridge, is lower, having a height 

 of 40 to 20 feet, declining southeastward, above the adjoining level areas, 

 from which, with their productive farms, it is distinguished, like the 

 higher mile at the west, by narrow but mostly continuous groves of small 

 oaks and other trees and underbrush on the lower part of either slope of 

 the ridge, while its rounded crest is a narrow avenue of prairie grasses 

 and flowers, of species that prefer its dry, gravelly soil. The course of 

 this part, crossing section 33, township 11 north, range 4 east, is from 

 northwest to southeast; and the crest was occupied, until at some places 

 fenced across in recent years, by a road for wagons, and long ago for 

 Indian ponies and their trailing poles. The width of the ridge along 

 this mile, from the foot of the slope on one side to that on the other 

 side, varies from 60 to 30 rods, decreasing southeastward. 



It is excavated only along a distance of about an eighth of a mile on 

 its southwest slope, midwa}^ between the center and southeast corner of 

 this section 33, for transportation by a railway spur track running to 

 the south. The section there is wholly coarse gravel, nearly level in 

 bedding, to the depth of 10 to 15 feet thus observed. No boulders were 

 seen in this excavation, nor along all the trail or road running on the 

 crest of the ridge for the mile and a half thence northwest, until, near 

 the western end of the esker, the road descends along its southwest slope 

 'to the village of Birds Hill. In that descent for an eighth of a mile 

 the roadway and the adjoining surface are strewn with boulders, mostly 

 granitic, up to 3 feet in diameter, which belong to the envelope of till 

 before mentioned. 



At the southeast corner of section 33 the esker sinks to the lowest and 

 most narrow part of all its course, rising only about 8 to 12 feet above 

 the general level on each side; and for a short distance there, some 40 

 rods or more, its usual accumulation of gravel and sand is replaced, or 

 is covered, by till with plentiful boulders. Perhaps this is a place where 

 till overlies a diminished deposit of esker gravel; but it appears to me 

 more likely that the esker deposit ceased there for a short space. Its 

 place is taken by the low ridge of till, gently rounded up, with a width 

 of about 30 rods or less, imitating in general form, but on a reduced 

 scale, the esker whose continuation it represents. 



Next eastward, in the south edge of section 34, this esker is again very 

 prominent, taking a course from west to east. It has been excavated by 

 the Canadian Northern Eailway Company on a width of 300 to 500 feet 

 for the distance of a mile through this section, the gravel and sand being 

 loaded on cars of spur railway tracks here running west and thence south. 

 The road on the south line of the section .rises about 50 feet above the 



