Geology of the St. Croix Dalles. — Bcrkey. 287 
Genus Euomphalus, Sowerby, 1812. 
Euomphalus strongi Whitrield, var. sinistrorsus, n. var. 
Euomphalus stroiii^i Whitfield. Ann. Rept. Wis. Geol. Survey for 
1877, p. 66, 1878. 
EuoMp/i a /us strou_^/ WhiiQekl. Geol. Wis., vol. lY , p. 200, 1882. 
Plate XX, Fig. 23. Plate XXI, Fig. 9. 
The specimen identified as £. strono-i presents the characters given 
by Whitfield in most particulars. These differences however should 
be noted. Number of volutions one and a half; cross section of body 
sub-circular, slightly sub-angular at the outer side; inner side decided- 
ly flattened and slightly indented by preceding whorl; coiled a little 
out of the same plane indicating a tendency to the sinistral spire. 
Formation and locality: Dresbach, Taylor's Falls, in the con- 
glomerate. Originally described from Baraboo, Wisconsin, by 
Whitfield. 
Gen.? sp.? 
Plate XX, Fife'. 2U. Plate XXI, Fig. 15. 
The specimen represented by these figures was the first one found 
of the large number from the conglomerates at Taylor's Falls. The 
figure is from a fragment of a mould and is not complete enough to 
warrant reconstruction and description. It appears to indicate a 
tendency to spiral coiling of the dextral type, about one-half volution. 
It is to be hoped that other and more perfect specimens may be found. 
TRILO BITES. 
Trilobites are found in the conglomerates at Taylor's Falls more 
abundantly than any other fossils with the exception of Olwllcla 
polita. In this case also a greater distribution is noted. Many speci- 
mens of a species of Dicellocephalus were found in the Franconia 
sandstone in a horizon at least lOO feet higher than the conglomerate 
strata. All but two specimens are referred to the genus Agraulus 
and are closely related as a group to A. convcxics Whitfield, the 
greater number of specimens clearly belonging to that species. One 
of the other above-mentioned specimens is regarded as identical with 
Ptychoparia [Conoceplialites) calymeiioides Whitfield, while the othe- 
is so clearly distinct from any form with which I am familiar that it 
is described as the type of a new genus. 
Genus Agraulus, Hawle and Corda, 1847. 
The trilobites found in this conglomerate are very closely related 
to A. convexus Whitf. Many specimens are no doubt of the same 
species while those showing a considerable difference have been as- 
signed new specific names. A considerable range of variation is al- 
lowed for Whitfield's species on the grounds suggested in a later 
paragraph. The described difference's are of necessity confined to 
the head parts and their proportions since the other parts of the 
animal are poorly preserved. 
