FEB 11 1892 



BULLETIN 



OF THE 



Scientific Laboratories 



OF 



DENISON UNIVERSITY. 



VOL. VI. PART II. 



WITH FIVE PLATES. 



EDITED l'.\ 



W. G. TIGHTJ M. S., 

 Departmeni ob Geology and Natural History. 



GRANVIlXE, OHIO, JANUARY, 1892. 



