A CONTRIBUTION' TO THE LoWER DEVONIAN FAUNAS OF MARYLAND 43 



It is not always easy to distinguish this species from T. aculus; but in 

 the latter the annulations are more closely and regularly arranged, espe- 

 cially on the earlier portions of the shell. In New York this species occurs 

 in both the Helderberg and the Oriskany. 



Occurrence. — Helderberg Formation, Coeymans Member. Dawson. 

 New Scotland Member, Devil's Backbone. Oriskany Formation, 

 Shriver Member. Cumberland, west side of Queen's Poiiit opposite 

 Keyser, Winchester Eoad near Allegany Grove. 



Collections. — Maryland Geological Survey, U. S. National Museum. 



Class CEPHALOPODA 



Subclass TETRABRANCHIATA 



Order NAUTILOIDEA 



Suborder ORTHOCHOANITES 



Family ORTHOCERATIDAE 



Genus ORTHOCERAS Breyn 



Orthoceras longicameratum Hall 



Plate LXXXVIII, Figs. 1-3 



Orthoceras longicameratum Hall, 1859, Nat. Hist. N. Y., Pal., vol. iii, p. 343, 

 pL Ixx, fig. 1; pi. Ixxl, figs. 1, 5, 1861. 



Description. — " Shell elongated, very gradually tapering; chamber ex- 

 tremely elongated. Septa numerous, highly arched, about four or five in 

 the space of the diameter of the shell. Siphuncle moniliform. Surface 

 unknown." Hall, 1859. 



The exact horizon is unknown. 



Occurrence. — Helderberg Formation. Cumberland. 



Collection. — U. S. National Museum. 



