546 ' GEOLOGY OF OHIO. 



Or.hoceras (Spyroceras?) Jamesi, Hall and Whitfield. 



(Plate 32, Fig. 3.) 



Quite a number of specimens, none of them of any considerable size 

 or length, have been found at the original locality, Todd's Fork, in 

 Clinton county, Ohio. 



Orthoceras (Cycloceras) amycus, Hall. 



• (Plate 33, Fig. 5.) 



A large specimen, not preserving the shell, was described from 

 Brown's Quarry (Proceedings Boston Soc. Nat. Hist., 1889, pp. 282, 

 283). A similar specimen from Ludlow Falls had annulations 26 

 mm. broad; five annulations occurred in a length of 21.5 mm.; 

 they were slightly more prominent than those of the Brown's Quarry 

 specimen. 



At Huffman's Quarry a very small specimen was found in the 

 upper shaly courses. It had 5 annulations in a length of 7 mm. 

 and the shell itself was about 9 mm. broad. In the " Orthoceras 

 block" from the same locality three specimens were found, 9, 13, and 19 

 mm. broad and with 5 annulations in 8.3, 11, and 15 mm. respectively. All 

 of these Huffman Quarry specimens showed transverse striae in addition 

 to the annulations, often distinct enough to be recognized without a lense. 

 In the smaller fragments so far found no measurable degree of taper- 

 ing is discovered. No longitudinal striae occur. The siphuncle is sub-cen- 

 tral and its sides are nearly straight, showing but a very slight degree of 

 contraction towards the septa. For a siphuncle of this kind it is very 

 broad, having a width of 2.5 mm. in the specimen 13 mm. broad. The 

 septa are of medium concavity, forming an arc of about 100°. 



Ortfioceras (Kionoceras) Craw/ordi, Foerste. 



(Plate 30, Fig. 26.) 



The type, collected at Soldiers' Home, is in the collection of Ira 

 Crawford (Proc. Boston Soc. Nat. Hist., 1889). The exterior of the shell 

 is ornamented by numerous fine distinct longitudinal striae of which 9 or 

 10 occupy a width of 2 mm. 



Orthoceras (Discosorus) conoideum, Hall. 



(Plate 36, Fig. 8.) 



Forms essentially like those figured from New York are not uncom- 

 mon in the Clinton group, at Todd's Fork, near Wilmington, Ohio. All 

 the specimens seen are in the cabinet of Dr. Chas. Welch, of Wilmington. 

 They are evidently the siphuncles of some cephalopod belonging to the 

 Orthoceratid^. 



