QI4 THE JOURNAL OF GHOLGOG Ns 
group in New. York. It also occurs, as does P. kallana in the 
lowest beds of the Chouteau group. 
Spirifer cf. compactus, Meek. A common species in the Chou- 
teau beds, is remarkably like Meek’s illustrations of S. compactus* 
from the Mackenzie Valley. If not referable to that species it 
can most certainly be considered as its genetic successor. 
Spirifer marionensis, Shumard. This is one of the most char- 
acteristic of Chouteau species. The form to which it is most 
closely related, through S. Whitneyz, Hall, of the lowa Devonian, 
is S. verneuil, Murch. Some of the variations of this most 
variable species? are closely similar to individual specimens of 
the American S. sarionensts. 
Eccyliomphalus paradoxus, Winchell. The nearest ally and 
probable genetic predecessor is found in &. daxus, Hall, from the 
Devonian of the east. | 
Loxonena cf. hamiltonae, Hall. In beds of the Chouteau group 
near Springfield, Mo., is a little species of Loxonema which can 
scarcely be separated specifically from this species of the New 
York Hamilton beds. 
Conclusion. From a consideration of all the evidence, the 
fauna of the Chouteau group is seen to be the resultant of the 
union of the two distinct faunas. Each of the original faunas is 
undoubtedly Devonian, but the resultant fauna as a whole has 
the strongest Carboniferous affinities. Before the removal of 
the barrier which kept them apart, these two faunas had lived 
under similar physical environments, and it is probable that 
either of them could have lived alone on the shores of the Ozark 
Island without undergoing any considerable change. But on the 
intermingling of two such distinct faunas, a fierce struggle for 
existence arose between them. In this struggle the most hardy 
elements of the two hardy faunas survived, and in their union 
resulted a most vigorous fauna which gave character to succeed- 
ing faunas for a long period of time, and whose influence was far 
* Trans. Chicago Acad. Sci. Vol. I., p. 102 (1868). 
2Etude sur les variations du Spirzfer vermeil, par J. Gosselett Mem. Soc. Geol. 
du Nord. (France) Tome IV., IJ., pp. 1-61, plates [.-VII. (1894). 
