PAGE. 



Figs. 40 to 44 CYRTOLITES SUBPLANUS Ulrich 862 



40 and 41 Two views of an incomplete shell, preserving the surface ornamentation. 

 Trenton group, Nashville, Tennessee. 



42 and 43 Parts of the dorsal slopes of same, x4 and x2, showing the strong transverse lines 



and weak pittings characterizing the species. 



44 Lateral view of a smaller but more complete example, with the surface markings 

 indistinct; from the same locality. 



Figs. 45 to 47 CYRTOLITES PARVUS Ulrich 864 



Three views of the type of this species, two of the natural size, the third *2. 

 Utica group. Covington, Kentucky. 



Figs. 48 and 49 CYBTOLITES DISJUNCTUS U. and S 864 



Two views of a very perfect example of this species. The surface is ornamented 

 almost exactly as in C. ornatus, so that figures 28 and 29 of this plate will serve 

 equally well for both species. 



Figs. 50 to 52 CYRTOLITES CARINATUS Miller : 862 



Three views of a small but characteristic specimen of this species, x2. Utica 

 group, Newport, Kentucky. 



Figs. 53 to 55 GYRTOLITINA NITIDULA Ulrich 866 



Three views, the first of the natural size, the others *2, of one of the original 

 types. The specimen is a cast of the interior but the shell was so thin that it 

 preserves a distinct imprint of the surface markings. Upper part of Trenton 

 group, Covington, Kentucky. 



Figs. 56 to 61 BUCANOPSIS CARINIFERA Ulrich 925 



56 and 57 Dorsal and lateral views of a large specimen. 

 58 Apertural view of the largest example seen. 



59 to 61 Three views of a third shell, this being of the usual size and proportions. 

 Trenton group, near Danville, Kentucky. 



Figs. 62 to 65 OXYDISCUS SUBACUTUS Ulrich 913 



(See also plate i. XAXIII 



62 and 63 Apertural and lateral views of a nearly perfect example of this species. The slit 

 portion of the dorsuin is broken in the specimen but has been restored in the 

 figures. 



64 Transverse section of a whorl, showing thickness of shell. 



65 Lateral view of the remains of the largest of twenty-three specimens. All the 



specimens are from the upper part of the Trenton group near Danville, Ken- 

 tucky. The figures are slightly magnified (about one and one-sixth). 



Fig. 66 CONRADELLA FIMBRIATA U. and S 907 



(See also plate LJCVII.) 



Vertical section showing transverse sections of all the whorls and portions of 

 former apertural expansions about two of the inner turns. 



Fig. 67 CONRADELLA ORANDIS Ulrich 908 



Transverse section of the last whorl of specimen figured on plate LXVII. 



Fig. 68 HELICOTOMA UMBILICATA U. and S 1034 



(See also plate LXXIV.) 



Transverse section of the whorls of a specimen from the Stones River group at 

 Dixon, Illinois. 



Fig. 69 HELICOTOMA VERTIQALIS Ulrich 1035 



Transverse section of the last whorl of the specimen figured on plato LXXIV. 



Fig. 70 ECCYLIOITEUUS BELOITENSIS U. and S 1032 



(See also plate LXXIV.) 



Transverse section of whorl. 

 Figs. 71 and 72 ECCYLIOPTEBUS VOLUTATUS Whitfleld ep 1031 



(See also plate i.xxiv.) 



Transverse section of the last whorl of two specimens, one with the shell, the 

 other an internal cast only. 



Fig. 73 ECCYLIOPTERUS TRIANGULUS Whltfleld sp 



(See also plate LXXIV.) 



Transverse section of the outer whorl of a cast. 



1031 



