SURVEY OF CAMPUS OF DENISON UNIVERSITY 
133 
soil which in places packs hard and is unfavorable for the growth 
of many plants. The entire region has been covered at least 
twice by ice sheets which left a thin and scattered deposit of 
glacial drift. In consequence the surface is quite gravelly at 
many places. 
Climatology. The data for this topic have been taken more or 
less completely from a report compiled by J. Warren Smith, 
covering the climate and weather in south central Ohio, in the 
general summary of climatological data for the United States. 
No records have been made in this area by the writer, but the 
data for Columbus, 28 miles distant, extend from 1878 and these 
have been used. 
The monthly mean temperatures in degrees Fahrenheit and 
and the average monthly rainfall in inches at Columbus are as 
follows : 
MONTHLY MEAN 
TEMPERATUKES 
(31 YEARS OP 
records) 
AVERAGE 
MONTHLY RAINFALL 
(30 YEARS OF 
records) 
January 
28.9 
2.97 
February 
30.1 
3.01 
March. 
39.6 
3.49 
April 
51.1 
2.84 
May 
62.5 
3.80 
June 
71.0 
3.41 
July 
75.2 
3.65 
August 
72.7 
3.21 
September. 
66.9 
2.41 
October 
54.7 
2.32 
November 
41.8 
2.91 
December. 
32.7 
2.66 
Annual 
52.2 
36.68 
Growing season 
66.6 
The absolute extremes of temperature for the central part of 
Ohio are 108° and —34°. These are important because of their 
possible effect in limiting the growth of vegetation, tending to 
control the northern limits of many species. 
