Jewell.] 466 [Jan. 18, 



Niagara group from Northern Indiana, showing a collection of 

 ■cephalopods upon which Professor Hyatt commented after the read- 

 ing of the paper, calling attention to the special importance of 

 many of the specimens. 



NIAGARA CEPHALOPODS FROM NORTHERN INDIANA. 



BY FREDERICK H. NEWELL, S. B. 



The cephalopods described below form a portion of the material 

 collected during a reconnoissance along the Wabash river in the 

 summer of 1887. This reconnoissance was undertaken for the pur- 

 pose of studying the structure of the rocks exposed by the river, 

 with a view to determining the amount and kind of disturbance, if 

 any, which that portion of the country has undergone. 



For the identification of the various strata numerous fossils were 

 obtained, and on careful examination of these I have found, among 

 the cephalopods, several new species of considerable interest. 



In this description the genera proposed by Professor Hyatt have 

 been used. 1 



I am under especial obligations to Professor Hyatt for his inval- 

 uable suggestions and criticisms during the study of these fossils. 



ORTHOCERATIDAE. 

 Genus ORTHOCERAS. 



The genus Orthoceras (Breynius), according to the classification 

 of Professor Hyatt, is "confined to straight and comparatively 

 smooth longicones with simple septa and sutures ; it equals group 

 17 of M.Barrande." 



By these definitions all the brevicones and the banded annulated 

 or striated forms of longicones are excluded. 



Orthoceras crebescens Hall. 

 Orthoceras crebescens Hall, 20th Rept. State Cab., of N. Y., rev. ed. p. 413, 



pi. 19, figs. 1-3. 

 Orthoceras crebescens Hall, Pal. Ohio, n, p. 148, pi. 9, fig. 2. 



Several specimens from Wabash City, Ind., are referred to this 

 species from the close agreement to the descriptions and figures 

 above noted. 



1 See Genera of Fossil Cephalopods, Proc. B. S. N. H., xxn, 1883, p. 253. 



