Plate IIIB 



Tig. 1. Crawfish chimney at Station I, Charleston, 111. Probably formed by CamlHin/s grac//is or 

 diooenes. (Photograph by T. L. Hankinson.) 



Fig. 2. General view at Station I. d, showing numerous crawfish chimneys, probably formed by 

 Cambarus gracilis or diogencs. (Photograph by T. L. Hankinson.) 



