1897.] The Pocket, or Pouched Gopher. 115 
Although the marginal outline of these mounds are usually 
circular, still, some of them are oblong, or have a gently flow- 
ing contour. 
These mounds are isolated from five rods to one mile from 
one another, or are closely and irregularly grouped, or arranged 
in rude circles, semicircles, or even straight lines. 
In some instances, we have counted as many as sixteen of 
these mounds in an area containing about two acres. 
The locations of these mounds are exclusively in the prairie 
regions, and may be found on either high and dry, or on low 
and rather moist land. In Iowa and Minnesota, where I 
have devoted considerable study to these “ peculiar mounds,” 
they may be seen for many miles over the level prairies. 
By far the greater number of these mounds owe their origin 
to the Pocket Gopher, (Geomys bursarius), which, year by year 
made additions to them by the dirt brought forth in the exten- 
sion of their underground channels, until they finally assumed 
the proportions now seen. 
Fic. 2. Geomys bursarius. 
Upon the death of the animal, or for some other cause, these 
mounds, and channels, were finally abandoned, and the 
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