NEW SPECIES OF GONIATITID^E. 135 



especially in the apparent extent to which the inner volutions 

 are embraced by the outer ones. 



Formation and locality . — In the Portage group, at Port- 

 age, N. Y. ; and in the Chemung group,, at Ithaca, N. Y. 



Goniatites Chemujstgensis var. equicostatus Sail. 



Among the GJ-oniatites of the Chemung group, there is a 

 single individual bearing considerable resemblance to the G. 

 Chemung ensis of Vanuxem {Report of the Third Geol. Dis- 

 trict of New York, 1842, p. 179, f. 48 2 ), but still differing too 

 much to be considered specifically identical. The form of 

 septa cannot be distinctly determined, but enough is seen to 

 show that they have the general characters of that species ; 

 but the volutions are more slender, and apparently more ven- 

 tricose, and the transverse ridges are more prominent, more 

 closely arranged, and extend more nearly across the volution. 

 At present it is indicated as a variety, until other specimens 

 may show more decidedly its true relations. The following 

 diagnosis gives the principal characters seen in the specimen : 



Shell of medium size ; volutions numerous, slender and 

 partially embracing, leaving a very broad, open umbilicus, in 

 which about one-half of each of the inner volutions is ex- 

 posed. Dorso-ventral diameter of the volutions nearly once 

 and a half as great as the lateral diameter, crossed by strong 

 transverse rounded ridges which are faintly marked or become 

 obsolete on the dorsum, and are strongest near the ventro- 

 lateral region ; the spaces between the ridges are rounded, 

 and of about the same width as the ridges. Septa divided 

 into several deeply marked lobes and saddles. 



Surface of the shell marked by line, transverse ridges, and, 

 in some places, there are indications of fine revolving striae. 

 This feature may possibly be the result of some external cause. 



Formation and locality. — In the Chemung group, near 

 Athens, Pennsylvania. 



