9 



LOCATION AND FIKLD OF OPERATIONS. 



Tlie Illinois River near Havana has a maximum width of about five hundred 

 feet at the lowest stage of water, and a maximum depth at that stage of ap- 

 pi'oximately 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, rang- 

 ing from forty to eighty feet in height, itself the edge of an extensive deposit 

 of glacial saud 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 lied of sand is not anywhere exposed 

 near Havana and has not been readied, so far as I have leai'ned, Vjy any b(n-- 

 ings 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 be- 

 tween the river and the bluff. 



The opposite or western bank of the river here 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 River winds its way, entering the Illi- 

 nois 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 along the bluff in the form of a narrow bay one and a half 

 miles in length, the so-called Quiver Lake, open to the river below, and I'e- 

 ceiving Quiver Ci'eek at its upper end. This creek, largely formed by the 

 drainage of a sandy tract to the east and north, empties into the broad and 

 shallow head of the lake through a muddy and weedy flat. Quiver Lake, like 

 the river below, has a sandy bank and margin on the east, and a mud bank 

 on the west. The natural drainage of the sand escapes in large quantities 

 along the eastern side of this lake, keeping the shore constantly saturated 

 with cold water, to a greater or less width according to the level of the lake, 

 and modifying greatly, when the river is low, the character of the Avaters of 

 the lake itself. A broad bay of this Quiver Lake extending to the west from 

 near its middle, forms what is known as Dogfish Lake, with shores of black 

 alluvial earth all around. 



The other waters of the vicinitj- included in the system of Station opera- 

 tions are Thompson's Lake, a shallow body of water about five miles long by 

 one mile wide, lying in the bottoms near the western bluff; Flag Lake, a 

 shallow muddj' pond or, more correctly, a marsh, about three miles in length, 

 largely overgi'own in summer with the club-rush, water-lily, and aiTowleaf; 

 and Phelps Lake, a small pond of dead water, three fourths of a mile in 

 length, with almost no vegetation, in the midst of a densely wooded bottom- 

 land. 



The field liead(iuarters of the Station party, tlie summer location of the 

 laboratory boat, was at the foot of Quiver Lake, against the sandy eastern 

 liattk. The top of the bliiff is here wooded at the edge and for a variable dis- 

 tance back with oak and hickory and ash and other common hard-wood 

 upland trees. Cottonwoods, walnuts, locusts, coffee-trees* elms, and {jecans of 



