Ecological Study of Brush Lake. 
GENERAL DESCRIPTION OF THE LAKE. 
RUSH LAKE is situated in the north-east corner of 
Champaign County, on the north side of the ‘‘ Pan- 
handle’’ Railway, at Brush Lake Station, about thirty- 
five miles west of Columbus. It is a pond covering 
about eleven acres, occupying a depression of the glacial deposit 
which covers the entire region for miles around. This deposit 
represents a moraine of recession and the surface is diversified by 
hills and hollows, the district being one of the most beautiful in 
central Ohio. In the neighborhood there are numerous small 
swamps and ponds, some of which have been entirely filled up 
with sediment from the surrounding banks and hills. It is said 
that Brush Lake was formerly about eighty feet deep. If this is 
true there has been a large amount of filling in recent times from 
the adjoining cultivated hillsides ; for at present the water is not 
over thirty-five feet deep in the deepest place. The elevation of 
the surface of the lake is given as 1,120 feet above sea level. 
There is a small ravine opening into the lake at the north- 
west and an outlet at the south-east from which water usually 
flows, forming a small brook, except in very dry weather when 
the loss from evaporation and other causes is greater than the 
supply. The outlet seems to be eroded very slowly and the 
decrease in the size of the lake due to this cause is at present 
insignificant. The water supply comes from a small drainage 
area and from springs which are evident on the west and north- 
west sides. From wells drilled at Fountain Park, about one mile 
south-east of the lake, it appears that the underlying rock is the 
Cedarville Limestone, belonging to the Niagara formation. There 
are several shallow artesian wells from this limestone at Fountain 
Park, but whether any of this rock water comes up into Brush 
Lake is not known. 
