readily accessible from the University, and that it should be 
attractive, comfortable, and convenient as a center of opera¬ 
tions for visiting investigators and for general and elementary 
students of our field biology. The purposed relation to fish- 
culture of course required that it should be on or near some 
lake or stream, or, better still, on some system of waters includ¬ 
ing both lakes and streams in large variety and in close prox¬ 
imity. After a careful study of the University environment, I 
selected in 1894 the Illinois Eiver and its dependent waters as 
our general field, and the vicinity of Havana, in Mason county, 
as the principal seat of our operations. (See map, Plate I.) 
Our two years’ experience here has served only to confirm our 
first impression, that a very suitable and, indeed, highly for¬ 
tunate selection had been made. 
LOCATION AND FIELD OF OPERATIONS. 
The Illinois Eiver near Havana (Plate VIII.) has a maxi¬ 
mum width of about 500 feet at the lowest stage of water, and 
a maximum depth at that stage of approximately ten feet. For 
a distance of about five miles, at the town and above and below, 
it runs along the foot of a steep sandy bank or bluff, ranging 
from forty to eighty feet in height (Plates II., XI., and XII.), 
itself the edge of an extensive deposit of glacial sand extending 
with little interruption some seventy miles along the eastern 
side of the river, and perhaps a dozen or fifteen miles in width 
from east to west. The bottom of this bed of sand is not any- 
where exposed near Havana and has not been reached, so far 
as I have learned, by any borings in that vicinity. From the 
foot of the bluff, at or near the water’s edge, is a more or less 
general oozing of clear cold water sometimes flowing forth in 
springs of considerable size and sometimes forming small 
marshy tracts betAveen the river and the bluff. 
The opposite or western bank of the river here (Plate X.) is 
of black earth, the border of an alluvial bottom three or four 
miles wide, in which are several ponds and lakes and through 
which Spoon Eiver (Plate XVIII.) winds its Avay, entering the 
Illinois nearly opposite the town. At the upper end of this five- 
mile stretch the river leaves the sandy bluff, having thence 
alluvial banks for some distance northward. The remnant of 
an old river bed continues upward, however, from this point 
