48 
large root, J to ^ inch in diameter at the base and 7 or 8 feet long. It never 
leaves the leaf mould layer, and remains mostly about 2 inches below the 
ground surface. These long, pliable roots are easily peeled and split, and 
have long been used by the Indians as sewing or binding materials for their 
birch bark utensils and canoes. 
Throughout these openings are small stream beds which evidently have 
had no flowing water in them for a long period. A little moisture may 
collect in them in the spring but it soon seeps away and leaves them dry. 
There are usually a great many large ant hills along the lateral slopes, with 
a few in the more or less flat bottom. The most interesting feature of 
these dry creeks is the presence in their beds of a quite different assemblage 
of prairie herbs, and, what seems entirely anomalous, it represents a more 
xerophytic association than the one that grows on the surrounding prairie. 
Many of its species are drawn from a group that inhabits such relatively 
dry plains as the river bluff at Peace point. The writer listed forty-one 
species, sixteen of which (one of them primary) do not occur outside the dry 
bottoms. The remainder are drawn from the immediate surroundings. By 
following up a creek bed one finds that it gradually shallows and that as it 
shallows it loses its peculiar flora, which is best seen at depths of 3 or 4 feet 
below r the level of the prairie. Deeper creeks present semi-marsh conditions. 
The following list contains only those plants peculiar to this type of terrain. 
The primary species are easily dominant over the scattered secondaries. 
Primary spp.: Carex siccata 
C. oblusata 
Secondary spp. : Festuca saximontana (A) 
Agroslis scabra (A) 
Poa glauca (A) 
Carex abbreviate 
Smilacina stellata 
Cerastium arvense 
Draba nemorosa (A) 
Geum triflorum 
Polentilla pennsylvaniea 
P. pulchemma 
Campanula rotundi folia 
Erigeron glabellus 
Aster laevis var. Geyeri 
Artemisia dracunculoides (A) 
Those marked (A) are commonest on the ant hills, and are among the 
most xerophytic of the lot. The blue-bell Campanula was found sparingly 
in the surrounding prairie, but was abundant in the creek bed. Carex 
obtusata, a predominant species here, was found elsewhere only on the drier 
parts of Peace Point prairie. This flora w r as found in both the 11- and the 
18-mile areas. 
The soil sections at the 18-mile area show increasing permeability with 
increasing depths. Between 24 inches and frost line, on June 26, was found 
a layer of pure sand interbedded with clay. On July 6 this was found to 
continue down to 41 inches in a nearby poplar grove. It seems clear that the 
creeks were once part of a temporary drainage system that carried the 
run-off from the exposed and rather impermeable bottom of the ancient 
lake in which these soils were laid. The streams continued until the moun- 
tain brooks into which they drained had cut deep ravines, and until they 
