1".).-, 



between the lower and upper Marcellus shales in Central 

 New York. The present specimen measures ;i little over 



an inch in greatest diameter. 



AMMONOIDEA. 

 Genus BACTRITES. Sandberger. 



[Ety. : Ba hi ron, ;i staff.] 

 (1841 : Leonh. und Bronn's Jalirbuch, p. 240.) 



Shell long, straight, slender, gradually tapering, round or 

 elliptical in cross-section. The siphuncle is thin and near 

 the margin. The sutures have very gentle lateral curves and 

 a funnel-shaped siphonal lobe. Theprotoconch isegg-shaped 

 and erect. 



B act rites gracilior. Clarke. (Fig. 229.) (1898: 

 Naples Fauna, p. 124, PI. IX. ) 



Distinguishing Characters. — Section of 

 uncompressed specimen sub-circular ; depth 

 of air chambers decreases relatively from 

 the older to the newer parts; septa quite 

 regularly concave, considerably oblique, 

 sloping toward the dorsum ; fine, con- 

 centric, oblique, closely crowded surface 

 lines on the young, and obscure, broad, 

 and low oblique ribs on the adult shell, all 

 sloping backward to the dorsum ; fine 

 vertical sub-equal lines on the body cham- 

 ber, seen only on well-preserved specimens. 



t-, -,. . c , i i i i Fig. ~ - . >, .i. Bactritea 



lor dlSCUSSlOll OI the development and gracilior. Internal mold, 



. showing septa and si- 



relations of this species, see ( larke s mono- phonal i .-niarged 



L (afl<-r Clarke). 



graph, referred to. 



This species occurs in the black shale of the Styliolina 

 band, at Section 1 (replaced by iron pyrites ). 



Baotrites aciculum. (Hall.) (Fig. 230.) (Coleolus 

 aciculmn. Hall. Pal. N. Y., Vol. V., Pt. II.. p. 187, PI. 

 XXXII.A.) 



1 



