398 
Borrom Fauna, 4—7-rr. ZonE, 1 Mire anove Liverpoot To Havana, 1915 
ar Small 
Viviparidae Insects, 
and pair axe worms, Total 
Pleuroceridae Sphaeriidae Crustacea 4 
Number per sq. yard, 
Average 120.8 3,537.3 172.0 3,830.1 
13 coll.’s 
Pounds per acre, 
Average 319.3 1,776.7 26.0 2,122.0 
13 coll.’s 
Per cent. of total, 
(By weight) . 15.0% 83.7% 1.2% 
Borrom Fauna, 1—3-rr. Zone, 1 Mite apove LiverPoot To Havana, 1915 
ee é Small 
Viviparidae Insects, 
and 5 Sean. worms, Total 
Pleuroceridae Sphaeriidae Crustacea 
Number per sq. yard, 
Average 230.6 38.5 81.0 350.1 
6 coll.’s 
Pounds per acre, 
Average 887.6 21.6 10.5 919.7 
6 coll.’s 
Per cent. of total, 
(By weight) 96.5% 2.3% 11% 
(e) Havana to Lacrance Dam (42.5 Mires) 
Hydrography—While the 42.5 miles of channel between Havana 
and Lagrange has on the whole a swifter flow than the flatter reaches 
above Havana, it is separable into three subdivisions which show dis- 
tinct differences in slope and current: . 
1. The 17.2 miles between Havana and Sheldon’s Grove (approxi- 
mately Sharp’s Landing), which has a low-water slope about the same 
as Liverpool—Havana (0.53 inch per mile, low water, 1901), and a flood 
velocity more than twice as great (140.91 feet per minute, March, 1903). 
2. The 13.3 miles between Sheldon’s Grove and one mile above 
Beardstown, which had a low-water slope in 1901 (1.08 inches per mile) 
about double that of the first 17 miles, but a flood velocity (116.06 feet 
per minute, March, 1903) less than that of the first section. 
