489 
2 CHANNEL COLLECTIONS, Ava. 6, 1915 
Foor or Granp ISLAND TO BROWNING 
(9-MILE SECTION OF NARROW, DEEP CHANNEL) 
Number per square yard| Pounds per acre 
Campeloma subsolidum 0.5 1.5 
AES. 2.7 
Pleurocera sp. 1.0 1.2 
Musculium transversum 5.0 5.0 2.5 2.5 
Chironomid larvae (small spp.) 1.0 trace 
6.0 1.0 
Hydropsyche larvae 5.0 1.0 
Total 012.5 6.2 
10 CoLLections, 4- To 7-FT. Zonrn, Ava. 6, 1915 
Foor or Granp ISLAND TO BROWNING 
(9-MILE SECTION OF NARROW, DEEP CHANNEL) 
Number per square yard 
Pounds per acre 
Campeloma subsolidum TANT 215.1 
Lioplax subcarinatus 1.6 1:9) 
Vivipara contectoides 14.9 92.4 74.5 307.9 
Vivipara subpurpurea 3.0 15.0 
_Pleurocera sp. 1.2 1.4 
Musculium transversum 106.4 106.4 53.2 53.2 
Chironomid larvae (small spp.) 1.9 0.2 
Hydropsyche larvae 0.5 0.1 
10.3 4.5 
Hexagenia, etc. (nymphs) 4.0 3.6 
Leeches (small spp.) 3.9 0.6 
Total 209.1 365.6 
