252 The Auieyican Geoloijist. April, is&7 
atonica belt. I tliink that a north and soutli belt of gravel 
knolls, two miles westof Freeport, belongs to this terminal line, 
having more of the nature of kames tha2i of a true esker belt. 
Following this line south of Yellow creek, it appears to pass 
into a broad smooth ridge of till, which crosses and complete- 
ly obstructs the preglacial valley of that stream. This same 
line is represented by discontinuous ridges extending across 
the divide into the Leaf river basin, where it is located by a 
■'special area" in the Adeline belt. 
The mapping of margin No. 5 is based solely on "special 
areas;" but in margin No. 6 we again find a pretty well de- 
fined line. The situation of this sixth terminal line is marked 
chiefly by a number of prominent angular gravel knolls, but 
it also intersects an important "special area" in the Pecaton- 
ica valley. This line was probably second in importance to 
No. 3 only. 
In addition to the six marginal lines of the Kansan drift 
sheet that I have here indicated, there are evidences of many 
more; but because of their indefiniteness I have preferred not 
to map them at present. It should be stated, however, that, 
wliile the more western margins have a tendency to project out- 
ward on a line trending northwesterl}^ from the city of Free- 
port, there is a straightening of the later terminal lines lying 
nearer the Pecatonica lobe of the lowan drift sheet, so that 
there is a discordance between the s^'^stems of the two glacial 
epochs. 
Conclusion. 
Reviewing this discussion of the eskers and intimately as- 
sociated deposits of the Pecatonica and Leaf river basins, I 
wish to call special attention to the following facts: 
1. Not only the trends of the individual ridges, but also of 
the completed esker belts, are always at right angles to the 
first terminal line west of a given point, and apparently par- 
allel with the general direction of luovement in contiguous 
portions of the ice-sheet, as indicated by phenomena inde- 
pendent of the eskers. By diligently observing the stratified 
drift, we may determine the direction in which the ice-sheet 
moved in every portion of the district. We thus learn that 
the general direction w^as west-southwest until it reached a 
line extending north and south across the Pecatonica basin, a 
