Figs. 
Figs. 
Figs. 
Figs. 
Figs. 
Figs. 
Figs. 
land 2 
a 
bo 
3 to 
SebOnno 
oo 
and 8 
9 to 14 
9-to 12 
15 to 17 
18 to 20 
18 
19 and 20 
21 to 25 
21 
30 to 32 
30 and 31 
32 
. 33 to 36 
. 37 to 41 
37 and 39 
38 
40 and 41 
42 to 46 
42 and 43 
44 
45 
46 
gs. 47 to 50 
47 and 48 
49 
51 
PLATE LXIX. 
TIOSPTIRA “ANGUSTACTA We cATG See ceever ie cciteiieenteieiie lie eietet tetelats sist siverek teats vefome 997 
(See also plate LXVIII.) 
Vertical section of a large specimen, chiefly a cast of the interior, showing 
thickness of shellin the umbilicus. The sutures in this specimen are unusually 
deep. Trenton group, Wykoff, Minnesota. 
Under side of the specimen figured on plate LXvuI (figures 35 and 36), showing 
the narrow umbilical perforation and thick shell surrounding it. Though 
the rest of this side of the specimen is a cast of the interior, the outer part 
of the last volution still gives a good idea of the surface markings. 
LAOSPIRA VITRU VPA SB UID S US elects ee wcrtets| ovesiepalotews aiateeberersstctoie obeere\emeeveleietetsieieie ie eatatatetalere 995 
Three views of a cast of the interior, from the Stones River group at Beloit, 
Wisconsin. The concavity of the upper side of the outer volution is usually 
somewhat less, while the hight of the casts is commonly a trifle greater 
among Minnesota specimens of this species. 
Vertical section of the cuter whorl of another specimen from Wisconsin, agreeing 
with the preceding and showing the outline generally pertaining to Wisconsin 
representatives of the species. Geological and Natural History Survey of 
Minnesota, Museum Register No. 7287. 
Vertical sections of two specimens from the Vanuxemia bed of the Stones 
River group of Minnesota, the first from Minneapolis, the second from Cannon 
Falls. Both retain the shell in the umbilicus and show, one more distinctly 
than the other, the angular border of the large umbilical perforation which is 
characteristic of the species. 
HOW OMAR TIANC A NGAULTIO ER Ava 0) TC la ereyerayatay oteyetataretetateracelalels siatarersvale eteralaveietetetonstersfeteaaieteterteisyayare 1002 
Four views of an average example of this species. Lowest division of the Stones 
River group, Murfreesboro, Tennessee. 
Surface markings of the upper side and contour of same portion, x2, of a large 
specimen from the same locality. The upper slope of the contour line is a little 
too steep in the figure. 
Outline view of a third specimen; the aperture is broken away but the spire is 
almost complete and shows the gradual increase of the apical angle, ~ 
MOTOMARTA'T ABTOSA: MUTE CH cise erers craderecactsvete/oters nis olekateisis oistelmeeinienteletieierete ei etic eRe eTEETS 1003 
Three views of a nearly entire silicified shell, showing the great strength of the 
inner lip which distinguishes the species from #. canalifera. Stones River 
group, Murfreesboro, Tennessee. 
MOTOMARTA AVICENIUD SMU ANG Secterretocicwastetersl= otolaVelstel siaters|elersia clalaiekererabete ieferaiete lien atalonatoes 1003 
Dorsal view of a cast of the interior from the Stones River group at Minneapolis, 
Minnesota. Geological and Natural History Survey of Minnesota, Museum 
Register No. 5106. 
Apertural and basa! views of a smaller and relatively higher cast from the same 
horizon at Mineral Point, Wisconsin. The species is c:osely related to H. dryope 
Billings sp., but has a more evenly conica: spire. 
HOMOWARTARD RY OL LOMAS VS peereieteyatete ciellokote etepele ale el Melaleie)isleje-atsvete eloiee= otalalal<tatatetalsusierele 1003 
Dorsal view of a large shell of this species from the Black River group of central 
Tennessee. Prof. J. M. Safford’s collection. 
Section of a whorl taken from a smaller specimen collected at the same locality 
as the preceding. 
Three views of a good cast of the interior, the spire slightly lower than usual for 
the species. Stones River group, Cannon Falls, Minnesota. 
HOTOMARTASSUPRACINGULATA BILIM OS'S Pere ct cress xo ele fas steleiarelcielsiel aretetelorel siete ema (aielmtars 1004 
Gutta percha impression from an incomplete natural mold of the exterior. Stones 
River group, Beloit, Wisconsin. 
Three views of a large specimen from Dixon, Illinois, retaining the shell, in a 
macerated condition, however. Figure 29 shows the remarkable forward sweep 
of the outer part of the under lip. 
WjTOSPUR As SUBCONG AcvAve Wi lL OH ye terete storey sie sierreranaloreteiters\steurtater= tnt ofateta atnatatanefovcterere tats Pursfeteiceyeines 999 
Two views of an average example. Stones River group, Murfreesboro, Tennessee. 
The upper side of a large specimen, from the same locality, showing the fine sur- 
face markings. The latter are more delicate than they appear in the figure. 
IPI O}sF IMT AG) iAoeV GUN ONbulalaconsdeony-7G0o0 boonSonD Cons Gono. seossogsnarndnaosose 999 
Four views of an average example of this species. The shell has suffered from 
maceration yet preserves distinct remains of the transverse wrinkles. Rich- 
mond group, McKinneys, Kentucky. 
FOV EN pecqopoagiopey.S, LON a(cltisos 55 snagasode on bban wods aqod sada 347990 b508 Abdcooosgass 999 
Two views of a specimen, medium in size and proportions. As usual the surface 
markings are very obscure. Upper part of Trenton group, Danville, Kentucky. 
Upper side of a similar specimen. 
Two views of a large shell, imperfect at the mouth but preserving unusually dis- 
tinct lines of growth. Formation and locality same as preceding. 
TETOSP TR As (7) VAIN UT AA MUO IY Ch ayetes eaters form icia) ofelevarctelslaantevelsiieietate oletsieulateieist sierra itso 1000 
Lower and Upp sides of a silicified shell, showing the angular border of the 
umbilicus. lack River group, Mercer county, Kentucky. 
Umbilical side of a cast of the interior from the same locality. 
A large cast of the interior, the inner whorls restored from another specimen. 
Locality same as preceding. 
Apertural view of original of figures 42 and 43. 
CLATHROSPIRA SUBCONICA. Hall Sp. ... 0.0.0 cece ence ce see nce svirieviss os sisisleielscieisiesl= 1006 
(See also plate Lxx.) 
Two views of acast of the interior from the Stones River group at Beloit, Wis- 
consin, showing an unusual feature in the large pits in the peripheral band. 
nother cast from Beloit with unusually strong ribs on the upper slope of the last 
volution. ; 
Cast of the interior of a large and typical shell from the Vanuxemia bed at 
Minneapolis. Geological and Natural History Survey of Minnesota, Museum 
Register No. 5037. 
CLATHROSPIRA CONVEXA U.. and S.... 2... cc cewcscccnccscssavacnasenas ce cuerce cove 1007 
Dorsal view of a specimen from the Stones River group in Calhoun county, 
TIllinois.. The upper slope of the whorls is more convex than in O. subconica. 
