Eskers of the K'nisan Epoch. — Hershaij. 245 
over the face of the glacier, or which welled up between the 
ice and its terraiual moraine. They indicate the position of 
the glacial front during a period of halt or slight readvance. 
Where moraines are well developed, kames are of inferior im- 
portance; but in the absence of distinct moraines, their exist- 
ence is of primary importance in determining the sub-stages 
of the general recession. To this class probably belong many 
of the small, apparently isolated, gravel knolls of the Pecaton- 
ica basin. Perhaps the " areas of special development'' should 
be included in this class, as they are essentially " terminal " 
deposits. Topographically and structurally, they combine 
features elsewhere peculiar to both eskers and kames ; but they 
may perhaps be properly considered as a sub-class by them- 
selves. Some of their characteristic features are due to their 
having been formed at the mouths of esker streams, where the 
ice-sheet was bordered by extra-glacial lakes. 
Transported Rock Masses. 
One mile north of the city of Freeport, on the low blulf 
which bounds the Pecatonica river valley, there is a small 
knoll of stratified waterworn gravel and sand, constituting a 
portion of one of our secondary esker belts. It is capped by 
a six foot stratum of angular limestone gravel. As this de- 
posit is typical of the class, we will examine the angular 
gravel closely. It consists exclusively of Galena limestone, 
the terrane which is exposed throughout the region. No drift 
pebbles of foreign derivation are found in this stratum. All 
the material is sharply angular, and in no portion of the de- 
posit does it show any evidence of water action. The mate- 
rial varies in size from fine sand to small boulders, and these 
are agglomerated in the irregular manner common to till. The 
same deposit appears in a neighboring quarry as a six foot 
stratum of broken rock, resting on the somewhat smoothed 
upper surface of the solid limestone. A portion of the angular 
gravel bed still retains evidence of the original stratification 
of the undisturbed rock. 
Half a mile east of Taylors Park, in East Freeport, a quar- 
ry has been opened into the west end of a short ridge. This 
quarry or pit exposes a thickness of eight feet of angular Ga- 
lena limestone gravel, and the base of the deposit is not seen. 
The original bedding planes of the rock have been generallj^ 
destroyed, except at one end of the excavation, where they 
