XII. 



Fig. 1. Blow-sand entirely without vegetation. A grove of walnuts (Juglans nigra) in the rear. 



Fig. 2. Traveling dune formed of sand removed from a blowout. A small thicket of plum-trees 



has been partially buried and the trees killed. A dense zone of Diodia teres grows around 



the edge. Robinia pseudacacia cultivated in the background. — The zigzag 



line at the edge of the sand is the track of a box-turtle 



(Cistudo Carolina). 



