JOE 
METHODS 
The survey and mapping of the habitats was carried on by 
townships. In the absence of outline maps of the separate town- 
ships, it was found necessary to make a copy of each on tracing 
cloth. These copies were based on an atlas of Johnson County* 
with such modifications as were patent from the work in the field. 
Each tracing was used to make a number of blueprints, on the 
scale of two inches to the mile, which were directly utilized in 
the field. 
Each blueprint for field use was cut into strips, approximately 
four inches wide, and mounted on heavy cardbord of the same 
width. The cardboard provided the necessary stiffness for writ- 
ing and was found useful for the inscription of notes in addition 
to the areas sketched on the map itself. These strips were of a 
most convenient size for slipping into the pocket and enabled 
the investigator to carry the map of the particular part of the 
township upon which he was then working without pene en- 
~ eumbered with the whole map. 
Accomplishment of this work in the amount of time available 
was possible only through the use of some rapid and dependable 
means of transportation, as the thorough mapping of some six 
hundred square miles of territory requires many hundred miles 
of travel along the roadways. This difficuity was met by the 
utilization of a Ford roadster. This machine, with its cyclometer, 
and a compass and pedometer in the pockets of the writer, 
enabled him to locate and estimate the size, direction, and extent 
of each habitat formation upon the maps with sufficient definite- 
ness to make each grove, thicket, pond, or bog quite easily found 
and distinguished by a stranger using the atlas. 
The analysis is the result of a series of field excursions over the 
county from September, 1913, to July, 1917. 
*Atlas of Johnson County, Iowa. Huebinger Survey and Map Publishing Company, 
Davenport, Iowa, 1900. 
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