ID* The American Geologist. Feb. isoj 
any single fauna] element in the various developments of the Her- 
cynian. This Hercynian discussion involves primarily the trans- 
ference of a certain fauna in the northwest llartz. considered by A. 
Reamer as upper Silurian, to the Devonian and as one of its conse- 
quences, the subdivision of M. Barrande's 'Silurian Basin" in Bo- 
hemia, leaving the Silurian to terminate with his etage e„ or with/ 
and referring/ 2 , g -\ ., and perhaps also H to the lowest Devonian. 
The controversy over these and other issues of the question has 
been prolific in literature for ten years past* and has an important 
hearing upon the Lower Helderberg fauna of North America and 
its relations to the normal Silurian (Niagara ) and to the Devo- 
nian. Dr. Novak's work does not, unfortunately, aim at com- 
pleteness. He has brought together certain trilobites occurring 
in the Rhenish and Westphalian Hercynian and with them com- 
pared similar or identical forms in the Bohemian. Not all the 
species or genera known from the German localities are introduced 
nor are some important Hercynian genera brought into considera- 
tion at all (notably Dalmanites). The following genera are dis- 
cussed : Pro&tus, An thus! n<i, Tropidoco'ryphe (new), Phcetonellus 
(new), CypJiaspio, Cyphaspides (new), Phncops, Harpes, Lichas T 
Acidespis } Cheirurus and Bronteus, and remarkably high percen- 
tages of the forty-one species and varieties described are found 
common to the German and Bohemian localities. Without enter- 
ing into the special bearings of these discussions there are some 
facts elicited which have an interesting relation to the trilobite 
element in American faunas of equivalent value. The great de- 
velopment of the Proeti ( nine species and one variety) is in sharp 
contrast to their meager representation in American faunas prior 
to those of the Upper Helderberg, and in consonance with their 
remarkable abundance and variety in these latter faunas. Of 
these proetids certain characteristic types are present both there 
and here. The most prolific there being species of the typical 
group, i. e. , conforming with the structure of P. cuvieri in hav- 
ing a regularly convex truncate-ovate glabella extending from 
*The writer has given a resume of the mere important phases of this 
discussion in the Report of the state Geologist of New York for 1888. 
Novak. Vergleichende Studien an einigen Trilobiten aus dem Her- 
i-yii von Bicken, Wildungen, Greifenstein und Bohmen. Dames and 
Kayser's Palaontologische Abhandlungen. Neue Folge. Bud 1, Heft 3, 
46 pp., 5 plates, 1890. 
