PLATE LXV. 



PAGE. 



879 



Figs, land 2 TETRANOTA MACRA U. and S 



Dorsal and lateral views of the type of this species. Stones River group, Minne- 

 apolis, Minnesota. The specimen is a good cast of the interior and shows the 

 expanded mouth, the peculiarly lean appearance and strongly ribbed charac- 

 ter of the fossil. 



Figs. 3 to 9 TETRANOTA SEXCARINATA U. and S 878 



3 and 4 Two views of an excellent specimen from the Fusispira bed at Wykoff, Minne- 

 sota. Though a cast of the interior, the surface markings are clearly indicated. 

 5 and 6 Dorsal and lateral views of a cast of an early variety of the species. Stones River 

 group, Minneapolis, Minnesota. 



7 Sectional view of preceding specimen. 



8 Section of a whorl of a specimen from the Stones Eiver group, at Dixon, Illinois. 



9 Section of whorl of Wykoff specimen. 



Figs. 10 to 18 TETRANOTA BIDORSATA Hall sp 877 



10 and 11 Two views of a large cast from the lower part of the Fusispira bed near Cannon 

 Falls, Minnesota. This specimen evidently has been somewhat compressed 

 laterally. 



12 Another cast tilted forward slightly to show the hight of the central ridge. 

 Clitambonites bed, Goodhue county, Minnesota. Geological and Natural His- 

 tory Survey of Minnesota, Museum Register, No. 7382. 



13 and 14 Two views of a specimen with the apertural parts broken away. Clitambonites 

 bed. 



15 Another specimen from the Clitambonites bed preserving the apertural margin 



with some of the surface markings on one side. 



16 Surface markings of same. x3 and x5. 



17 Ventral side of fragment of outer volution showing transverse section of same 



below and four grooves produced by the dorsal ridges of the preceding whorl. 

 Clitambonites bed. 



18 Dorsal view of a small specimen. The majority of the specimens seen from 



the Clitambonites bed range in size between this and figure 13. 



Figs. 19 to 23 TETRANOTA OBSOLETA U. and S 880 



19 and 20 Dorsal and apertural views of a testiferous example on which the slit-band has 

 remained concave throughout the growth of the shell. Ctenodonta bed, Chat- 

 field, Minnesota. 



21 to 23 Three views of the specimen which we regard as the type of the species. Though 

 retaining the shell, we have failed to discover any remains of surface markings. 

 Ctenodonta bed, Goodhue county, Minnesota. 

 Figs. 24 and 26 TETRANOTA, sp. undet 880 



24 Dorsal view of a good cast of the interior from the Utica group at Cincinnati, 



Ohio. This specimen may represent a later variety of T. bidorsata Hall, but in 

 the obsolesence of the latero-dorsal ridges, as may be seen from the basal out- 

 line, it agrees more closely with T. obsoleta. 



25 Dorsal view of a cast of the interior of an undescribed species of this genus. 



Stones River group, Minneapolis, Minnesota. The ridges in this species, of 

 which our material is not sufficient to warrant us in giving it a name, are 

 unusually obscure. 

 Figs. 26 to 29 TETRANOTA WISCONSINENSIS Whitfleld sp 881 



26 Dorsal view of a large anrt nearly perfect cast of the interior. Stones River group, 



Heloit, Wisconsin. Collection, University of Wisconsin. 



27 View of same with the smaller volutions removed, showing the ventral side of 



the outer whorl with the four furrows which are always found here in species 

 of Tetranota. 



28 Lateral view of same. 



29 Dorsal view of a very small specimen supposed to be the young of this species. 



Minneapolis, Minnesota. 



Fig. 30 SCHIZOLOPIIA TEXTILIS Ulrich 992 



A specimen showing the slit in the outer lip and preserving some of the delicate 

 surface markings. The enlargement of the latter (x2) represents part of the 

 upper third of the last whorl to the suture line and above this the slit-band of 

 the preceding whorl. Upper part of Trenton group, Nashville, Tennessee. 



Figs. 31 to 37 SCHIZOLOPH A MOOREI Ulrich 992 



31 and 32 Two views of a nearly perfect cast of the interior of the typical form of this species 

 showing the slit, the great prominence of the carina on the last whorl, the 

 umbilicus, and other characteristic features. Richmond group, Richmond, 

 Indiana. 



33 Gutta percha impression from a natural mold of the exterior, showing the coarse 



surface markings. Richmond, Indiana. 



34 Outer third of the last whorl of a specimen overgrown by a species of Protarea, 



which originally covered all of the exterior of the shell excepting the slit in the 

 aperture. Locality, same as preceding. 



35 Transverse section of the last whorl of a cast from the same horizon and locality. 



The small indentation on the umbilical side (left sidu .. figure) is characteristic 

 for the typical form of the species. 



36 Transverse section of the last whorl of a small variety occurring in the Lorraine 



group at Cincinnati, Ohio. In casts of this form the peripheral angle is less 

 prominent than in the typical form, and there is no indentation on the umbil- 

 ical side. (Compare with figure 35.) 



37 Vertical section of an unusually high, testiferous example of the Cincinnati 



variety. 



Figs. 38 to 40 LOPHOSPIRA (?) KNOXVILLENSIS Ulrich 989 



38 and 39 Umbilical and apertural views of a specimen showine the general form of the 

 shell, which is much as in Trochonema, with the distinct peripheral band of a 

 Lophospim. Knoxville, Tennessee. (?Chazy group.) 

 40 View of the umbilical side of another specimen from the same locality. 



Figs. -11 to 44 LOPHOSPIRA ? TIIOCIIONEMOIDES Ulrich 990 



Four views of the type of this species. 



