Williams.] FAUNAL DISSECTION OF THE DEVONIAN. 49 
pardiola, as strictly interpreted, and the name Glyptocardia was pro- 
posed as a new generic name in 1885 a to take its place, the fact that 
in Europe as well as in this country this generic name has been 
applied to this species and its European representative makes it not 
inappropriate as a name for the fauna. As Hall observed in discuss- 
ing this species ( Glyptocardia ( Cardiola) speciosa Hall) : b 
It is probably identical with the Cardiola retrostriata (von Buch) of various 
authors, and with Cardium palmatum of Goldfuss. Its citation by numerous 
authors shows its wide distribution in Europe. 
The fourth fauna of the list (D) — that of the Chemung formation 
of the east — is the Spirifer disjunctus fauna. The species Spirifer 
disjunctus is undoubtedly identical, specifically, with the form which 
is more commonly called Spirifer verneuili by European geologists. 
There are several varieties of it which are present in some regions 
in which the typical form Sp. disjunctus is wanting. 
These four faunas may now be named and distinguished. In the 
discussions that follow, the relation to these of other faunas, which 
may eventually be classified as distinct, will also be considered. 
THE STATISTICS AND THE PLAN OF DISCUSSION. 
After the publication of the classification set forth in the paper of 
1880 c * a large number of investigations were undertaken, not only in 
New York, but in other parts of the country, which throw new light 
upon the questions then raised. But nowhere have the statistics been 
so well gathered as in New York State. Particularly valuable have 
been the researches of Prof. 0. S. Prosser. Other contributions have 
been made by N. H. Darton, J. M. Clarke, S. G. Williams, G. D. 
Harris, C. E. Beecher, J. J. Stevenson, E. M. Kindle, Stuart Weller, 
A. W. Grabau, and H. F. Cleland. Many others have taken part 
in accumulating the statistics, dissecting the faunas into faunules, 
and analyzing the faunules, more or less perfectly, into their specific 
values, as expressed by abundance or raritj^and in terms of frequency 
of appearance in successive stratigraphical zones or at distributed geo- 
graphical stations. The particular part of the geological column about 
which the fuller statistics are gathered is also that part of it which 
was selected in 1881 for special investigation — i. e., the middle and 
upper formations of the Devonian system. 
In order to illustrate the method, and to demonstrate the few gener- 
alizations which at the present state of the investigation are fairly 
well established, these statistics of the Devonian will be digested and 
interpreted in the following ways, viz : 
The order of discussion will be : First, a presentation of the facts 
regarding the faunas; second, the dominant and characteristic spe- 
a Palaeontology New York, Vol. V, Pt. I, Lamellibranchiata, II, text, p. xxxv. 
blbid., pp. 426-427. 
c Classification of Upper Devonian: Proc. Am. Assoc. Adv. Sci., Vol. XXXIV. 
Bull. 210—03 4 
