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Figs. 
1 to 9 
1 
2and 3 
co wast & 
10 to 13 
10 and 11 
12 and 13 
14 to 16 
17 and 18 
19 to 21 
19 
20 
21 
22 to 26 
22 
23 and 24 
25 
26 
27 and 28 
27 
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29 and 30 
29 
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31 and 32 
33 and 34 
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45 and 46 
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49 
PLATE LXXVUI. ~° 
PAGE. 
TROCHONEMA -BELOITENSE WIG] diye ce oc cose re cere ete lelstaie otasoteto ler ete tele ene (oot etetetetaiolategs 1048 
Dorsal side of a cast of the interior. from Beloit, Wisconsin 
Umbilical and dorsal views of a well marked specimen of the form of the species 
prevailing at Dixon, Illinois. Excepting the umbilical region, which gives an 
idea of the thickness of the shell, the specimen is a cast of the interior. 
Three views of a large example, retaining most of the shell, from Mineral Point, 
Wisconsin. 
Gutta percha impression of a natural mould of the exterior, from Beloit, Wis- 
consin. 
Dorsal side of an interior cast of the Minnesota form of the species, having the 
last whorl partly free; Minneapolis. 
Under side of a similar specimen from the same locality. 
TROCHONEMA. VAGRAINS) (Ui: IGS erctasveterolate tote intaye otatewereystarererereieie bevel ieiate icra eiererea ete ices 
(See also plate LX XVII, fig. 46.) 
Basal and lateral views of a cast of the interior, from Minneapolis. 
Similar views of a nearly perfect cast from the same locality. Survey collection, 
Museum Register No. 6865 
GYRONEMA. HIRATUM WU. and Sinner eee ase eee cece ele iiirieeieece repre soit 
Three views of the specimen upon which this species is founded, While the 
greater part is preserved as a cast of the interior, a portion, as shown in fig. 14, 
is of the exterior. Beloit, Wisconsin. 
GYRONEMA* SEMICARINATUM Salter, Spij--iectels aalcisis cis cietete belie tetera ieee elas 
Dorsal views, natural size and x2, of a specimen retaining the shell; near Cannon 
Falls, Minnesota. 
GYRONEMAS PUM CHEE (Mie ena asses heleystere ie peeetalorele eters belnisisietarsiaie siatetn lata Te De sesneeyenice 
Dorsal view of a small but nearly perfect example; Chatfieid, Minnesota. 
Portion of same x5 to show extremely fine lines of growth. 
Apertural view of a larger and excellently preserved specimen; Minneapolis. 
Geological and Natural History Survey of Minnesota, Museum Register No. 
6854. 
GYRONEMAS DUPICA TU Me iW eS ere acre tele varsie erecta stcterstatey a oto ntets aoraints eveteraieteteleee neler 
Side view of a specimen which retains some of the shell and has a higher spire 
than usual; Dixon, Lllinois. 
Apertural and dorsal views of a large and almost entire cast of the interior 
belonging to the collection of the University of Wisconsin: Beloit, Wisconsin. 
The lower whorl of a cast of the exterior from the same collection and locality. 
CYCLONEMA (?GYRONEMA) PRCIPTUM, n. Sp. (Ulrich.) ............2+ 2-22.20 eeees 
Dorsal view of an average example of this species; Stones River group, Murfrees- 
boro, Tennessee. It was through a species like this that Cyclonema was evolved 
from Gyronema. The inner lip is relatively thicker, straighter, and more reflexed 
than in species of Gyronema, but not excavated as it should be in a true 
Cyclonema. A minute umbilicus is often present. This species is referred to 
but not named in the fifth paragraph on page 1046. 
(GhaoleOrcnoniON aU Ceofsjopi, MaMa dms Ses code coe Coa OAnOnSeoD GorecutcoossnSade saan 
Apertural view of a specimen from the upper part of the Trenton group at Nash- 
ville, Tennessee. 
Dorsal view of a larger specimen, from Colby, Kentucky. The inner lip is nearly 
vertical and the carin very strong in this species. 
CY CTONEMAGME DLAI sUSITI CM sterscrebteteteieietetel ot=terdia’e tare eb atniel i ctetaofetelelinas efelerehetete de ateleatataieaiete 
Dorsal view of an average example of the typical form of this species; Covington, 
Kentucky. In another common variety the revolving carine are less equal, 
being more as in fig. 34 of this plate. 
Under side of another specimen from Covington. 
GVGT ONE MAS EN DR TACT UMM TILT CHD preset sesre etcetera oie teed neta epee leveled fates te botevel hen stateietelatelatevetatstetetete 
Dorsal views of two specimens from Cincinnati, Ohio, showing rather extreme 
conditions in the manner of growth. The apex in the first is entire. 
CY. CLONEMA SP YsB/A MADD AT UM eh INES ate feyarelar ave teinis ior <fateteyatatel hatatorokalielaltotateneteleloiete (stati et siiale 
Basal and dorsal views of a typical example of this species; from the vicinity of 
Morrow, Ohio. ; 
(Qh cerrarspoe\arinrio-< {Clyne once deoonobocndbcogotocoongcbboasa deacons onAusnamsas000 
Dorsal view of a rather large example of this species, from Versa'lles, Indiana, 
A similar view of a smaller specimen, from Waynesville, Ohio. 
A dorsal view of a third specimen, from Clarksville, Ohio. These three speci- 
mens are regarded as agreeing in every respect strictly with the original type of 
the species. It is to be observed that the revolving carinz are not as strong as 
in CU. mediale, and the suture more abruptly impressed. 
Dorsal views of two specimens of the form which Miller proposed to distinguish 
as variety conicum; from Versailles, Indiana. 
CYCLONEMA BILTIX Var. FLUCTUATUM JAMES). << 6.2.5 oe vere se misicnis siete minis =u celle 
Dorsal view of a perfect specimen of this variety, from Versailles, Indiana, show- 
ing the relatively fine revolving lines, oblique folds and concave slopes of the 
whorls which usually characterize this variety. 
Two views, x5, of the apex of same. 
CYCLONEMA HU MEROS UI Ulli Chiesa peteee rela tats cereal ete ate eke lahelsietetelleletoleleeutatel=!aie]= aisles 
A large and strongly marked specimen of the Richmond group variety of this 
species; Waynesville, Ohio. Possibly this is an extreme variety of C. bilia, with 
which it was found associated, rather than of the Lorraine group types of this 
species. 
Apertural view of a large example of an abundant variety in the Lorraine group 
at Cincinnati. The whorls are more rounded and the ‘‘shoulder” less distinct 
than in the typical form of the species. 
Dorsal and basal views of a typical example from Cincinnati. The shoulder at 
the top of the whorls is often more pronounced. 
CYCLONEMA SIMULANS Ulrich................ gya'n td Qlaibva lave fnlatare eielehetel a lee ele eee tee 
Dorsal view of an average example of this species, showing the rather delicate 
revolving lines growing more and more obsolete on the last volution; Cincin- 
nati, Ohio. 
CYCLONEMA SUBD AOVIE UITICH ss cies cerave 3se miosis a ayae' stein © piaiclaieielebstet ental ser aie eee isieraie(» 
Dorsal view of a representative example; Covington, Kentucky. 
Similar view of a relatively higher specimen, from the same locality. 
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