96 



Fig. 2. Bunch-grass at the Devil's Hole. The bunch-grasses and the cactus plants 

 are discernible. Wind action is starting on the slope to the left. 

 Beyond is the very large blowout shown in Figure i of this plate, 

 which has now reached the stage known as the blowsand complex. 

 This same area of bare sand is seen also in Figure 2, Plate IV. 



Plate III 



Fig. I. A nearly typical blowout at the Devil's Hole. The basin is shown in the 

 center, the windward slope at the right, and the blowsand association 

 of the lee slope in the right background. The forest in the rear is 

 the black oak of the ridge between Crane Creek and the Black-jack 

 Ditch. 



Fig. 2. Summit of "Tower Hill", north of the Devil's Neck. The "tower", a 

 rude platform used by the Illinois River Survey, was blown over 

 early in 191 1. Dunes of Rhus canadensis illinocnsis to the left. The 

 blowout is being actively excavated. 



Plate IV 



Fig. I. An area of almost bare sand showing the very sparse vegetation. The 

 Rhus dune to the left is being blown away. 



Fig. 2. The sandy waste known as the Devil's Neck — a large blowsand complex 

 three miles north of Topeka, Illinois. Most of the area is quite 

 barren. 



Fig. 3. The large bare sand area at the Devil's Hole. The entire windward ex- 

 posure of a dune has been denuded of vegetation — a not infrequent 

 occurrence. 



Plate V 

 Mixed forest of the Quiver Lake marginal dune, north of Havana. 



