KNIVES 



THE CHICAGO ACADEMY OF SCIENCES 



The 



Paleontology of the Niagaran Limestone 

 in the Chicago Area 



THE TRILOBITA 



BY 



STUART WELLER 



OF THE UNIVERSITY OF CHICAGO 



BULLETIN No. IV. 

 PART II. 



OF 



s 



THE NATURAL HISTORY SURVEY 



ISSUED MAY 20, 1907 



