448 
an elevation of 670 feet, or forty feet above the river, and twenty 
feet higher than the ridge on the east side of the East Branch. This 
region is rather heavily timbered, the trees being large and the 
ground being covered with an accumulation of debris, showing that 
the area has not been disturbed by man. About a third of a mile 
west of the East Branch a large ridge is encountered which is very 
abrupt, rising suddenly from a level plain and gradually sloping 
toward the south until it reaches the level of the surrounding area. 
This was probably a sand spit extending into Skokie Bay. Small 
ponds, like those found in the area east of the East Branch, are 
generally absent, although there are several ponds and semi-marshy 
spots at the foot of the sand spit mentioned above. Several small 
streams drain into the East Branch during the spring, but aside 
from these, this area is quite free from summer-dry ponds, owing, 
probably, to its greater elevation and the absence of large depres- 
sions in which water might gather. 
To the south, this territory is cleared for pasture and farm land, 
and the same may be said of the areas bordering the Shermerville 
road, which cuts through this portion of the region. Bordering the 
river to the north, the ground is lower and forms a wet, marshy 
area in spring. This is especially true of those portions of the terri- 
tory to the north of the Glencoe road. 
E. The North Branch of the Chicago River. 
(Plate XVIIL., 2.) 
This stream, which is not of an intermittent character as is the 
East Branch, is from twenty to thirty feet in width and is quite 
deep. It flows through a low area, the banks also being low, just 
a foot or so above the stream, and the territory on either side is 
swampy and reed-grown. East of the St. Paul railroad bridge, the 
river forms an extensive arm at the foot of the railroad embankment, 
which is marshy and supports a fauna different from that of the 
river proper. The river flows through the village of Shermerville 
and is becoming contaminated with sewage, like the larger stream 
at the southward. This area was found to be very poor biologic- 
ally. 
