840 : THE PALEONTOLOGY OF MINNESOTA. 
[Scenella compressa. 
This species resembles S. superba Billings sp., but is readily distinguished by its 
more depressed form, horizontal aperture and finer surface markings. The muscular 
imprints also are much stronger than in that species. 
Formation and locality.x—Stones River group, Vanuxemia bed, Beloit, Wisconsin. 
Collection.—Ubiversity of Wisconsin, No. 307. 
ScENELLA COMPRESSA, #1, Sp. 
PLATE LXI, FIGS. 38—41. 
Shell small, compressed conical, the hight exceeding the longest diameter of 
the aperture, while the shortest diameter is to the hight as three is to five, or as 
two is to three; apex subcentral, laterally compressed, inclining forward slightly; 
back and sides of shell obscurely flattened, anterior part sharply rounded; aperture 
subovate, narrower in front than behind. Surface with fine radial lines, three or 
four in 1 mm., and somewhat irregular transverse lines and wrinkles. The shell 
seems to have been rather thick and the surface markings are not visible on the 
cast. Length 138 mm.; width about 9.5 mm.; hight 14.5 mm. 
This peculiar species reminds one somewhat of the much larger S. magnifica, 
but we do not think its relations to that species are very intimate. Its affinities 
are probably nearer to S. montrealensis Billings sp., yet not enough so to render 
confusion between them at all likely. The narrowly rounded anterior slope and 
the flattening of the sides and dorsum are obvious peculiarities. 
Formation and locality.—Stones River group, Vanuxemia bed, Minneapolis, Mionesota. 
Collection.—K. O. Ulrich. 
SCENELLA AFFINIS, ”. Sp. 
PLATE LXI, FIGS. 36 and 37. 
Comp. Metoptoma montrealensis BILLINGS, 1865, Pal. Foss., vol. i, p. 394. 
Comp. Tryblidium conicum WHITFIELD, 1886, Bull. No. 8, Amer. Mus. Nat. Hist., p. 306. 
Shell small, conical, with the apex subcentral and directed slightly forward, 
the anterior part compressed, especially for a short distance beneath the beak 
where it is almost angular; aperture somewhat irregular, subovate, narrowest in 
front; in a side view the anterior outline is slightly convex in the middle and 
correspondingly concave above to the apex; behind the latter the outline is gently 
convex to the margin. Surface exhibiting very fine, easily abraded, concentric and 
radiating strix, and some irregular wrinkles of growth. Length 10 mm.; width 
9 mm.; hight 7.5 mm. 
This form is probably a variety of S. compressa, distinguished by its lower and 
wider shell and finer surface markings. It seems also to be very closely related to 
