Figs. 
Figs. 
Figs. 
Figs. 
Figs. 
Figs. 
Figs. 
Figs. 
Figs. 
37 to 41 
37 
38 
39 and 40 
41 
HORMOTOMA: SUBANGUDGATAS Wii MGiSieni. bres) careers olela\alaroinjotey mien slr nicierel sjereloi aie pel teeetetenereys 
Cast of the interior, apparently of this species. Clitambonites bed of the Tren- 
ton group, Cannon Falls, Minnesota. 
A small testiferous specimen from the Ctenodonta bed of the Black River group, 
Goodhue county, Minnesota. 
Two views of a larger example. Ctenodonta bed at Chatfield, Minnesota. 
Two whorls of the original of fig. 38, x2, showing band and surface markings. 
42 and 43 HoORMOTOMA GRACILIS var. GOODHUENSIS U. and S... «2.1... sce ce cece cece cc ee tees 
Two specimens found in the Phylloporina bed of the Black River group near 
Cannon Falls, Minnesota. 
44 to 51 HORMOTOMA SALTERT Wi) mich Wy cicicncioeslociletee eis beter tltaeteleterteeieletseiaiel-toiet sistas ies 
44 to 47 A series of four specimens selected from several hundred to show variation in the 
rim-like thickening of the upper edge of the whorls in the typical form of this 
species. Fig. 44 is the most like the var. canadensis (Murchisonia [Hormotoma] 
gracilis Salter, not Hall sp.) in which the rim is scarcely distinguishable. Upper 
part of Trenton group, Mercer county, Kentucky. 
48 Two whorls of the original of fig. 47, x2, to show the surface markings, band and 
outline of whorls more distinctly. 
49 A small imperfect specimen, x2, of var. tennesseensis, from the Black River 
limestone of Tennessee. Has finer and more equal lines of growth than the 
typical form of species. 
50 Doubtful specimen from the same formation and state as the preceding. The 
shell is too thick and the whorls relatively too high. 
51 A third fragment from this locality that is doubtful because the band is too 
wide. A fourth example from the same locality seems to be identical with the 
var. canadensis. 
62) tos 5d ISOLENOSPIRAY PRISCAY BIT PISS iota ste eyelet kate fe cetera ese baty serie aYereba = eta l=Tod= eleiel stat elele/a eit etay=lalenetete 
52 Silicified specimen of var. extenuata. Lower division of the Stones River group 
at Murfreesboro, Tennessee. 
53 Diagrammatic figure made up from gutta percha impressions of several incom- 
plete moulds of the exterior collected at Beloit and Janesville, Wisconsin. 
54 Two whorls of the Tennessee form, x2. 
55 Three whorls of the northwestern form, x2, showing that they are relatively 
wider than in the Tennessee variety. 
a to) GLU Soe ISO MsiE ney. Wie. WeroDYA SNhi@ie gs Sab Snaesconcacooncapscs ocapcdsonboudepaccecoder sons 
56 and 57 Two views of a fragment, showing the form of the mouth, the four revolving 
caring and several of the fine lines of growth. The latter show that the outer 
lip is notched and that the space between the central pairof ridges represents 
a true slit-band. Phylloporina bed of the Black River group, near Cannon 
Falls, Minnesota. 
58 Same specimen in another view, x2, to show the form of the volutions more 
clearly and to admit of easier comparison with S. prisca. 
59 and 60 The apical portion, natural size, and two whorls x2, of a specimen from an equiy- 
alent horizon at Porter’s station in Wisconsin. Collection of Wisconsin 
State University. 
POA EY CEB Olan) ecoYod. Wop mors pcorisOM OLN ONO Wr e seloc tor dang o00G0 os SDOL Asp Sonpstog coo snomsos 
Two casts of the interior and the base of one, showing the numerous depressed 
whorls and the narrow umbilical perforation. Trenton group, Jo Daviess 
° county, Illinois. 
64andi6d, OMOSPLRA LATICUNGMASUIBICH: qomitcisise ictal aieeieole lit )alalmin/atesaae sisi alelsiretele «/si-inl> lela w(e e1c|a/«f- 
64 A large testiterious example of this species, imperfect below and at the apex. 
Black River limestone, Tennessee. 
65 A slightly oblique view from above of a portion of the last whorl of same, x2, 
showing the course of the regular lines of growth. 
66.and 6% OMOSPIRA ALEXANDER Ay Billi SiS Ph pepe ioteye hats ehelnserst-1-/ teeta letelnietalel sistelalein/elessteletel=lelelsaisicl= 
66 An imperfect silicified shell of this species, from the top of the Black River lime- 
stone of Mercer county, Kentucky. The whorls are more rounded than in the 
preceding species. : 
67 A cast of the interior from the same formation at Dixon, Illinois, doubtfully 
referred to this species. : 
GS lan GiG9 SMO MOMPAUS TA eenTe MV SATIVA UM GINM fetets tetelatateietslegetettayeteate elegeke ce Coleterale ate aed eiateliteel= cata tee terete 
Two views of the nearly entire type of this species. Trenton group, Hartsville, 
Tennessee, 
1015 
1016 
1022 
1022 
1020 
945 
946 
1005 
