226 ILLINOIS ACADEMY OP SCIENCE 



It is of more than iDassing interest to compare at this 

 point the difference in the aspect of the clay bluff in its 

 early stages of stabilization as studied by Dr. Cowles in 

 1900 (see Fig. 12), and the aspect in 1918 (see Fig. 13), 

 and to note how rapidly the vegetation spreads over the 

 bluff once the slope has become gentle and stabilization of 

 soil has begun by means of vegetation. 



d. The upland mesophytic climax association. — There 

 were two places where the upland mesophytic climax for- 

 est type was found ( see map ) . One was north of Kavine 

 4 (jSTewhall), (see map, N. T. 6, 31 and 11) ; the other 

 appears just south of Dell Place and continues south 

 along the lake bluff. 



The forest to the north might well represent a typical 

 primaeval mesophytic forest. Fig. 11 shows the gentle 

 angle of slope and how complete the stabilization has 

 become, owing to the dense growth of vegetation. Most 

 of the trees were large, i. e., eight to twenty inches in 

 diameter. All the shrub species were very abundant, in 

 fact, they together with the numerous saplings formed an 

 almost impenetrable thicket. The remnants of herbaceous 

 vegetation together with the species represented in the 

 other life forms indicated a high degree of mesophytism. 

 Quercus rubra, Fraxinus americana and Ostrya virginiana 

 were the dominant species here. Associated with these 

 trees were Quercus alba, Quercus macrocarpa, Quercus 

 ellipsoidaJis, TUia americana, Populus grandidentata, 

 Populus deltoidcs, Acer saccharum, Juniperus virginiana, 

 and one specimen of Pinus strobus. Quite large trees of 

 Juniperus virginiana formed a border nearly twenty feet 

 wide along the lower edge of the bluff. All of the trees 

 recorded were reproducing abundantly. Even a sapling 

 of Pinus strobus was found. 



In company with the trees were the following shrubs: 

 Cornus stolonifera, Cormis circinata, Cornus paniculata, 

 Viburmim dcntatum, Viburnnm acerifolium, Viburnum 

 lentago, CoryJus americana, and Rhus typliina. There 

 was a luxuriant growth of lianas along the base of the 

 bluff. Lonicera (sp. ), Vitis (sp.), and Celastrus scan- 

 dens were the ones recorded. 



