1895.] Geology. 159 
Dean on Coprolites.—In the description of a new Cladodont 
shark, C. newberryi, from the Ohio Waverly, Mr. Bashford Dean refers 
to a coprolite found with the specimen, as follows: 
“Tt (the coprolite) is especially interesting, since it furnishes a cast 
of the intestinal wall, and gives definite evidence as to the presence of 
aspiral valve. This structure accordingly maintained in the general- 
ized Cladodont, and that the intestinal septa were here low and numer- 
ous is most significant phylogenetically. Its condition in this form, as 
the nearest known ancestor of Selachians, would, moreover, give an ad- 
ditional reason for emphasizing the most ancient origin of Dipnoan, 
Teleostome, and even Chimeroid.” 
This discovery of Dr. Dean throws a light upon certain sorew-like 
fossils described under the names Spiraxis, Spirangium, etc. Newber- 
ry’s descriptions and figures of Spiraxis major and S. randallii, from 
the Chemung sandstone, are identical with the coprolite figured by Dr. 
Dean from the intestine ofthe shark. The inference, then, is that many 
of these screw-like forms from geological horizons, in which sharks are 
numerous, and which have been referred by different investigators to 
Algæ, are in reality coprolites. (Trans. N. Y. Acad. Sci., Vol. XIII, 
1894.) 
New Molluscan Forms from the Dakota Formation.—So 
little is known of the fauna of the Dakota formation that great interest 
is attached to the discovery by Dr. Hicks of some invertebrate remains 
in Jefferson County, Nebraska. The Dakota strata in this locality 
consist of ferruginous limestone, the fossiliferous layers being impure 
limonite. The fossils are all either vegetal or molluscan, and are in 
the condition of natural casts, molds or imprints. The mollusca were 
referred for identification to Dr. Charles A. White, who describes and 
figures them in the Proceedings of the National Museum. The col- 
lection comprises five new species and two doubtful ones, all indicat- 
ing unmistakably, in the author’s opinion, a purely fresh-water fauna. 
In his concluding remarks, Dr. White refers to the unusual inter- 
est attached to these new forms by reason of the following facts: 
“Tt is one of only three collections of invertebrate remains from 
the Dakota formation. It indicates, more distinctly than any previ- 
ously discovered facts have done, the nonmarine character of that 
formation. It embraces four genera which have never before been 
recognized in collections from its strata. Lastly, although this forma- 
tion lies at the base of the Upper Cretaceous series, a majority of the 
species which this collection contains belong to genera representatives 
