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40 NEW YORK STATE MUSEUM 



would seem to foe supported by the finding of a specimen of 

 S. bilineatum in the Rysedorph hill 1 conglomerate by 

 Dr Emmons. There are, however, some facts which combat 

 such a view. These are the observations of Clarke; that the 

 alternation of the striae is more distinct toward the apical 

 region and by rapid intercalation becomes less pronounced 

 toward the aperture; farther, that a shell of S. bilineatum, 

 with a diameter of 7 mm, had only 12 lines of the first order, 

 while the shells under consideration, with a diameter of only 

 3 mm, have already about 20 striae; that no trace of the 

 fine transverse lines, appearing on all stages of S. bili- 

 neatum, has been observed thus far; and finally that the 

 small shells of Rysedorph hill taper exceedingly slow, while those 

 of S. bilineatum taper quite fast. A fragment f inch long 

 shows no measurable increase in diameter. Orthoceras 

 a n e 1 1 u s Conrad differs in just these features from 0. bili- 

 neatum and it suggests itself that these shells, if not a new 

 species, are very likely to be the apical portion of O. anellus, 

 hitherto not observed, and also, that O. anellus is a typical 

 Spyroceras. 



Spyroceras bilineatum has been found to range in 

 the east (Canada) from the Black river into the Trenton beds, in 

 the west to begin in the Stones river beds, and Spyroceras 

 anellus begins in the Black river beds and extends into the 

 Trenton. (Group 7) 



(Cyrtoceras) subaimuiatum d'Orbigny sp. Pro dr. de pal. 1850. 1:1 

 Cyrtoceras annul a turn Hall. Pal. N. Y. 1847. 1 :194 

 A fragmentary specimen characterized as belonging to Cyrto- 

 ceras a n n u 1 a t u m by its strongly arcuate annulations, fine 

 transverse lines and central tubular siphuncle, was found in a 

 pebble of greenish gray compact limestone. This species was 

 obtained by Hail from the lower and upper Trenton beds of 

 New York. (Group 7) 



