270 A NATURALIST IN THE GREAT LAKES REGION 



The steep soil slopes that lie at the base of the rocky cliffs 

 bear a forest of black, red, and white oaks, with chokecherry,hop 

 tree, water beech, hop hornbeam forms which are characteristic 



of such slopes. Witch- 

 hazel is the predominant 

 shrub. The ground is 

 covered with large areas of 

 the cinnamon fern and, 

 lower down, the inter- 

 rupted fern. 



There is an abundant 

 bird population in these 

 wooded slopes. Wood 

 thrush, hermit thrush, Wil- 

 son 's thrush, the ovenbird, 

 indigo bunting, cardinal, 



FIG. 412. The spotted sandpiper. 

 Forbush. 



After 



black-billed cuckoo, crested 

 flycatcher, and Baltimore 



oriole are among the commonest inhabitants. Chickadees nest 



in the old woodpecker holes. 



On these moist slopes snails are particularly abundant. 



Practically all the Polygyras of the Chicago area are found here. 



P. dlbolabris and clausa, fra- 



terna, fraudulenta, hirsuta, 



inftecta, monodon, multilineata, 



oppressa, palliata, pennsylvanica, 



thyroides, Pyramidula alternata, 



solitaria, perspectives; Omphalina 



fuliginosa, friabilis; Circinaria T FlG ' 4i 3 -Long-bodied spider, 



1 etragnatlia laborwsa. 



concava; Zonitoides arboreus 



these are all present. In the early morning after a shower or 

 after a heavy dew the ground and the low vegetation is fairly 

 alive with tHese numerous species. They are common in the 

 river bottom also, and are found crawling on the paths and 

 roadways (Figs. 284, 285). 



