September, 1943 Brown & YEAGER: 
regions, and the separate sampling of each 
regional area. 
Fur Survey Regions 
A number of factors, rather than soil 
alone, were used as criteria in dividing 
Illinois into regions suitable to the pur- 
poses of this survey. “These criteria, in 
SURVEY OF FuR RESOURCE 
439 
lift, fig. 3. The northwestern corner 1s 
also unglaciated and is somewhat broken 
and rolling. ‘The erosional effects of the 
Mississippi River on the west, the Ohio 
and Wabash rivers on the south and east, 
and the Illinois River, extending south- 
westerly from Chicago nearly to St. Louis, 
lower the prairie status of the state and 
make for an appreciable area of river bot- 
Table 1—Fur survey regions and data on field samples used in Illinois fur animal survey, 
1938-39 and 1939-40. 
AREA OF anne AREA OF Per Cent Per Cent 
Fur SurvEY REGION, County Se a SAMPLE, OF OF 
REGION SQUARE SAMPLED S oa SQUARE CountTY REGION 
MILEs oe MILEs SAMPLED SAMPLED 
Northwest Hills. 821} Jo Daviess 623 79.50 12.76 9.68 
Western Prairie. 3,244) Hancock 765 109.75 14.33 3.38 
River Bluffs and Calhoun 282 fe ae 
Regan... 11,251] Union ca 685! 99 006 154-99l9 33¢ 22.48 1.37 
Northwestern 
Sand Prairie. . 4,526| Lee 724 108.00 14.92 2.39 
Glacial Lakes... 1,638} Lake 483 91575 18.99 5.60 
Bilack..Prairie:. . . 16,462} Champaign 988 111.00 Lhe2s 0.67 
Central Sand 
Prawie fF .24% - 5,697| Mason 554 101.00 Loee3 Lae 
Gray Prairie... . 13,026} Franklin ae Hatant 26.29 
fiinoise) ss... .. 56,665 10 Sus DG 28 OO is eee Tate, 1/0 
their order of importance, were as fol- 
Meet) soil, (2) forest ‘cover, (3) 
drainage, (+) topography, (5) fur ani- 
mal distribution, (6) agricultural use and 
(7) latitude. 
On the basis of the above criteria, the 
state was divided into the eight regions 
listed in table 1 and shown in fig. 2. For 
purposes of accurate area calculation, the 
dividing lines between all regions were 
run north-south or east-west, and there- 
fore only approximate the true boundaries. 
The area of each region is given in table 1. 
Various soil, drainage, topographic and 
cover maps were studied as an aid in defin- 
ing the boundaries of areas over which 
uniform fur yields might be expected, figs. 
3 and 4. 
Although recognized as a prairie state, 
Illinois is more or less diversified in soil, 
climate, topography and agriculture. The 
southern one-third is relatively rough and 
hilly, climaxed geologically by the eastern 
extension of the unglaciated Ozarkian up- 
toms and bluffs. Three definite sand areas 
and several larger sandy-soil regions fur- 
ther diversify the soil types of the state. 
Illinois has a total area of 56,665 square 
miles, of which 622 are inland waters. 
‘The state ranks twenty-third in area and 
third in population. Seventy-five per cent 
of its boundary is water. Its length from 
north to south is 385 miles; its greatest 
east-west width is about 215 miles. For 
effect of latitude see “Project Objectives.” 
Physiographical features of Illinois were 
determined largely during the glacial 
epoch. “The moraines throughout the 
northern half, the numerous kettle lakes 
in the Chicago region, the till and loess 
deposits, and the prairies are directly re- 
lated to glacial advances and retreats. A 
brief description of the eight fur survey 
regions follows. 
Northwest Hills——This, one of the 
state's two unglaciated areas, is locally 
termed the “Little Switzerland of IIli- 
nois.” It is very small, the fur survey 
