104 College of Forestry 
XIII. Shallow Creek Type, Quiet Protected Pool. 
Station XVI.*| When a protected spot occurs in the bank 
of a rapidly flowing stream (as the previous type) a type of 
habitat is formed quite different from the hurrying waters 
of the near-by stream. These pools are filled with algze and 
animal life is usually abundant. 
MOLLUSCA. 
Planorbis trivolvis, common. Physa gyrina, common. 
Planorbis hirsutus, common. 
CRUSTACEA, 
Amphipod (Hyalella knickerbockeri), common. 
INSECTA. 
Water beetle (Tropisternus gla- Damsel-fly nymph (Hnallagma spe- 
ber), common. cies), common. 
Fig. 30. Diagrammatic map of vegetation island in outlet at Brewer- 
ton. 2, 3, 4 depths of water. 
Y. Carex. 0. Nymphea advena. 
X. Dianthera americana. 0. Castalia odorata. 
-Scirpus occidentalis. + Potamogeton natans. 
* Pontederia cordata. 
3. River Type. 
Stations XXXVI, XX XVIII. In this type of habitat, 
which is afforded by a narrow strip of water bordering the 
river bank, the bottom is muddy or sandy, the water is from 
1 to 8 feet in depth and there is a quantity of vegetation, such 
as: 
