286 TJic American Geologist. May, iss^ 
lU'l/a, but on account of the great hight of shell and resemblance to the 
p-cceding forms in everything save the almost central apex and the 
almost straight sides, I prefer to leave them in this genus. 
Hypseloconus stabilis, n. sp. 
Plate XIX, Figs. 2.") and 26. Plate XXI, Fig. 6. 
Form conical, straight, almost imperceptibly inclined toward the 
broader margin; surface smooth; sides direct; apex central, smooth 
and bhmt; aperture oval; hight i8 mm.; length 14 mm.; width 12 mm.; 
apical angle 45 °. 
Formation and locality: Upper Dresbach, Taylor's Fails. 
In addition to these just described a number of coiled forms identi- 
fied as species of Eitomphalus and Sccevogyra, and others whose po- 
sition is not known, have been found. 
Genus Scaevogyra, Whitfield, 1878. 
One species of this peculiar type was found at the same locality 
with those already mentioned. Inasmuch as all the species of 
SccEvogyra so far described belong to the Baraboo fauna as reported 
by Whitfield, there is additional evidence in this St. Croix dalles oc- 
currence of the essential identity of the two faunas as a whole and indi- 
rectly of the unbroken continuity of the strata to which they all belong. 
In comparing these fossils with descriptions of similar forms from 
the Cambrian strata, one can scarcely escape the conviction that 
Platyceras primordiale Hall* from the "Potsdam group" is not a true 
P/atyce?-as and the same might be said of all species referred to this 
genus from the Cambrian. P. priinordiale is with considerable cer- 
tainty referred to the genus Scavogyra. 
Scaevogyra minnesotensis, n. sp. 
Plate XX, Fig. 26. 
Cast of shell showing a sinistral coil of one and a half to two vo 
lutions; apex raised just above the body whorl; expanding rapidly; 
aperture defective but showing an indication of the trumpet form of 
S. s-wezeyi Whitf. A few lines parallel to the aperture are regular, 
otherwise smooth. 
The elevation, number of volutions, and aperture are sut^cient to 
distinguish it from the known species. 
Formation and locality: The Dresbach at Taylor's Falls in the 
conglomerate. 
*i6th Rep. N. Y. Mus. Nat. Hist., 1863, p. 136. 
