314 

 ORTHOCERAS MISSISQUOI. (N. sp.) 



Fig. 303. 

 Fig. 303. Siphuncle of 0. Missisquoi, the most common form. 



Description. No specimens of this species with the septa preserved 

 have been found, but the siphuncle, represented by the above figure, 

 occurs in great numbers in one locality, in B 2, at Phillipsburg,. The 

 most commqn form (of the siphuncle) is three or four inches in length, 

 gently curved, tapering at the rate of about one line and one-third to the 

 inch, and marked by from nine to twelve septal rings to the inch. As 

 these rings are most distant from the apex on the concave side, it is 

 evident that the position of the siphuncle, in the fossil, is near the shell 

 on the dorsal side, or on the side of the concave curve. 



Associated with this short curved form, there are numerous others, 

 more elongated, somewhat straighter, and not quite so rapidly tapering. 

 The septal rings are sometimes more rounded, or more like the annulations 

 on such shells as 0. arcuoUratum. Similar differences are exhibited by 

 the detached siphuncles of other species. I think all the specimens 

 found at this locality belong to one species, variable to spme extent in its 

 length and rate of tapering. It probably is like a large gently curved 

 Cyrtoceras, from six to .ten inches in length, with the siphuncle on the 

 inner instead of the outer curve, and with a diameter at the aperture of 

 from one to three inches. 



Locality and Formation. Phillipsburg, B 2, section Geol. of Can., p. 

 844 ; Quebec group. 



Collectors. Dr. P. J. Farnsworth, and E. Billings. 



ORTHOCERAS CATO. (N. sp.) 



Description. Shell of medium size, somewhat rapidly tapering ; section 

 apparently circular ; septa nine to the inch ; siphuncle very slender, 

 cylindrical, in contact with the shell or nearly so ; chamber of habitation 

 deep ; surface with rather strong thread-like engirdling striae, about four 

 in one line. The shell appears to be plain, but in one part there seems 

 to be some indistinct annulations. 



The specimen is 3i inches in length, somewhat flattened, evidently by 



