9^9 



Winchell.] ^'^'-' [Jan. 4, 



width of the valve, shghtly produced anteriorly. Dental lamellae extend- 

 ing three-fifths the length of the valve, not apjiroximated at the rostral 

 extremity. Muscular scars striate. Surface of cast destitute of plica- 

 tions, but deeply marked toward the front by wrinkles of growth. 



Transverse diameter, one and five-eighths inches ; antero-posterior di- 

 ameter, one inch ; heiglit of area, three-eighths of an inch. 



This species is more completely destitute of plications than any other 

 in rocks of the same age ; and this character, together with the length, 

 width and flatness of the area, renders it necessary to admit it as new. 



Spirifeba Carteei, Hall {S. Vernonensis, Swallow). Yery abundant 

 in bed No. 4, Sciotoville, Ohio ; rare in bed No. 5, Rockville. A single 

 specimen labelled Granville, is, probably (judging from the matrix), from 

 Sciotoville. Occurs also, near Shafer's, Penn. 



Spirifeka Mariokeksis, Shum. (Mo. Geol. Rep., Pt. ii, p. 203, pi. C, 

 fig. 8, a — d.) Several specimens from bed No. 4, Sciotoville, Ohio. These 

 specimens agree tolerably well with the description of this species, and 

 with specimens from Clarksville, Mo. This seems to be a species, how- 

 ever, which exhibits a tendency to graduate on the one hand, into 8. M- 

 plicata, and on the other, into 8. Carteri Young specimens exhibit a 

 well defined ventral sinus, with about two incii^ient plications; and having, 

 at this age, sharper dorso-lateral angles, they closely approximate S. bipli- 

 cata. Large specimens, on the contrary, can scarcely be distinguished 

 from 8. Carteri, save by the less pronounced sinus and fold. 



There are, indeed, six species described from rocks of this age, which 

 need to be re-examined and compared, viz : 8. ATarionensis, Shum., 1855; 

 8. Carteri, Hall, 1857-8 ; 8. hiplicata, Hall, 1858 ; 8. Vernonensis, Swal- 

 low, 18G0 ; 8. Osagensis, Svval., 1860 ; and 8. Missouriensis, Swal., 1860. 

 The three first are, perhaps, distinct species — possibly all the others. 



Spiripera subrotundata, Hall (Iowa Geol. Rep., p. 521). From 

 bed No. 4, Sciotoville, Ohio. 



On some of the casts no striations are certainly seen, except over a lim- 

 ited space one side of the beak. 



Spirifera BiPLiCATA ? Hall. A single imperfect specimen, from No. 

 4, Sciotoville, Ohio. See remarks above on 8. Marionensis. 



Spiriferina solidirostris, White (Bos. Jour. YII, 232). Collected 

 by Rev. H. Herzer, at Newark, Ohio, and by Prof. Andrews, from bed 

 No. 4', Sciotoville, and bed No. 5, Rockville. 



Syringothyris typa. Win. (Proc. Acad. N. S., Phil.) This species 

 occurs quite abundantly in Ohio. Mr. Herzer and Prof. Andrews have 

 furnished over a dozen specimens from Newark. In bed No. 4, Scioto- 

 ville, it forms, with 8pirifera Carteri and several other species, the prin- 

 cipal mass of a highly ferruginous stratum of sandstone. It occurs 

 freely, also, near Shafer's, in Pennsylvania. 



From Newark specimens may be worked out good views of both valves, 

 and of the bifariously striated area. Traces of the pseudo-deltidiura may 

 also be seen, and it appears that the dental lamellte are very deep, but the 

 essential structure of the genus does not appear. Tliere is one exceptional 



