284 The American Geologist. May, i89n 
Hypseloconus recurvus ( Whitfield), var. elongatus, n. var. 
Metoptoiiia recurva Whitfield. Ann. Kept. Wis. Geol. Survey for 
1877, p. 61, 1878. 
Metoptojiia recurva WhitHeld. Geol. of Wis. vol. IV, p. iq6, 1882. 
Plate XVII, Fig. 1. Plate XIX, Figs. 1 and 2. Plato XXI, Figs. 2, U aud 21. 
Shell conical, very high, upper portion of shell curved very moder- 
ately toward the broader posterior margin of the aperture; apex 
slightly posteriorly excentric, smooth and erect; aperture entire, plane, 
and a very flat oval in outline, broader posteriorly; length 21 mm; 
width 16 mm; hight of shell 32 mm; surface bears strong growth 
plications or fine growth lines or is entirely smooth. Apical angle, 
40°x30°; apical excentricity 5 mm. 
Formation and locality: Upper Dresbach, Taylor's Falls con- 
glomerate. 
In addition to this particular form there are among these speci- 
mens many individuals showing marked differences among themselves 
but connected in each case by intermediate forms, and whose exist- 
ence makes further subdivision at this time inadvisable. The more 
prominent of these individuals are figured in plate XIX. Figures 5 
and 6 represent a peculiarity of the anterior slope similar to that noted 
by Whitfield in T. [Mctoptonia) retrorsa. This peculiarity resolves 
itself however into a mere constriction of the aperture during its 
later growth and cannot be considered very important. It shows 
though in addition a more acute aperture anteriorly than most of the 
specimens. This individual is also represented in plate XXI, fig. 12. 
(a) Figs. 3, 4, 7, 8, 21 and 22 are forms intermediate between the 
type (as represented in figs, i and 2) and that figured by Whitfield 
(as M. recurva). These are all recurved, the apex is anterior to the 
center, but the posterior slope is not nearly so abnormally developed 
as Whitfield's specimen. Plate XXI, fig. 16, is from a photograph 
of one of these specimens. 
(b) Figs. 29 and 30 represent a specimen with apex much extend- 
ed. The aperture also is much more rounded than most of the forms. 
. The posterior slope resembles the figure by Whitfield more closely. 
(c) Figs. 23 and 24 and also fig. 13 of plate XXI represent two 
specimens whose anterior slope is irregular indicating a constriction 
of aperture; and the aperture is noticeably sub-triangular. 
(d) Figs. 13 and 14, 15 and 16 represent a few specimens in which 
the apex is decidedly more excentric even submarginal, and the gen- 
eral appearance of the form gives one the impression that there is a 
strong tendency to form a coil. 
Differences in proportion are apparent by measurements, but these 
are no more satisfactory in subdivision than the points to which at- 
tention has just been called. In studying this fauna it has been found 
convenient sometimes to refer to the different groups within this 
species by varietal names. The type specimen (H. recurvus var. don- 
