CORRELATION OF THE DEVONIAN FAUNAS 635 
CONCLUSION. 
It is believed that the facts here set forth satisfactorily 
demonstrate that the Devonian faunas in southern IIlinois are not 
related to the Iowan Devonian faunas as has sometimes been 
suggested, but are a western extension of the faunas of the New 
York province. Atthe “ Bake Oven” section the fauna of the 
lowest beds is of an age corresponding to the lower portion of the 
Upper Helderberg period, while the uppermost faunas are of 
Hamilton age. The line of demarkation between the Upper 
Helderberg and Hamilton faunas cannot be exactly drawn, but 
it comes somewhere between zones 54 %5 and 5A *3. 
In conclusion I wish to acknowledge the assistance given by 
Mr. A. W. Slocom, who has skillfully prepared the material for 
study. 
STUART WELLER. 
THE UNIVERSITY OF CHICAGO. 
