437 
exceed the average figures obtained by us in 1916 in the same depth 
zone in the isolated glacial lakes of northern Illinois (105 lbs.), but do 
not average much if any better than the best littoral areas in Deep and 
Cedar lakes (Deep Lake, gravel bottom, 220 lbs., clay and rotten vegeta- 
tion, 320 Ibs.; Cedar Lake, sand and clay bottom, 251 Ibs.). They com- 
pare very well with the all-depth average (one to eleven feet) for the 
Illinois Valley lakes of all classes in 1914 and 1915 (255 lbs. per acre), 
but are exceeded by the general average of bottom fauna only in the 1—6- 
foot zone of our Class I lakes in the Havana district (441 lbs.) ; and are 
far surpassed by the figures for the 1—3- and 4—?-foot zones of the 
Illinois River between Copperas Creek dam and Havana (1—3-foot 
zone, 919 Ibs. ; 4—7-foot zone, 1,960 Ibs.). The ratio of Mollusca to the 
total weight of all animals averaged much higher (38% to 64%) than 
in the glacial lakes of northern Illinois, but was far under the ratios 
found in the Illinois River and in the lakes near Havana. 
Bottom Fauna or ONEIDA LAKE, 1—6-root ZONE 
POUNDS PER ACRE (OUR VALUATIONS) 
nroniusen | Associated | cay | Her cont 
| 
Sand bottom 251.3 | 138.3 389 64 
Mud bottom 96.9 133.5 230 42 
Sandy clay 81.4 129.3 210 38 
Gravel 139.4 68.2 207 67 
Clay 75.3 112.7 188 40 
. 
While Baker found in Oneida Lake, in a few situations, a weed fauna 
(total, picked by hand from plants removed from the water) that ap- 
proached in valuation his bottom-fauna averages for the littoral zones, 
the average productivity indicated ran very low, and even his heaviest 
collections (57 to 207 lbs. per acre, our valuations) were far below 
those obtained by us in the lakes of the Illinois Valley near Havana 
(2,118 Ibs. average) or in the thick Potamogeton and Ceratophyllum beds 
of Nippersink and Pistakee lakes (1,655 Ibs.). Baker’s best figures were 
obtained in the Potamogeton and Myriophyllum, and the bulk of the 
collections by weight was made up of snails. 
