1918] ROBBINS—BOULDER PARK 507 
stream course, the shores were eroded and an inlet of considerable 
width and depth formed. We take it that the position of this is 
represented by the long tongue of sedge moor that extends from 
the lake edge to the meadow. Soil borings here show deep deposits 
of peat extending to the meadow. 
At present, East Lake has a flat bottom and a uniform depth of 
about 1 ft. The bottom is of mud. The lake’s development is 
Fic. 8.—View of East Lake, of oxbow origin; beyond is portion of large terminal 
moraine, 
natural and typical of an oxbow belonging to the lower terrace. 
The associations in and about the pond are arranged concentrically, 
particularly along the west and south sides. A small amount of 
Batrachium and Callitriche is found in the water. Carex utriculata 
makes a pure association chiefly along the west shore, where it is 
rapidly pushing out into the water. The plant is 1-2 ft. high and 
spreads by means of creeping rootstocks. Its typical habitat is 
still water not exceeding 1 ft. in depth. The amount of plant 
remains annually deposited by it is considerable. F urthermore, it 
