williams.] FAUNAL DISSECTION OF THE DEVONIAN. 67 
Sellersburg faunule, Lexington, Scott County, Ind. 
Chonetes yandellanus (abundant). 
Tropidoleptus carinatus (abundant). 
Spirifer granulosus (common). 
Stropheodonta demissa (common). 
Roemerella grandis (rare) . 
Phacops rana (rare) . 
Proetus canaliculatus. 
Stictopora sp. ? 
Cystiphyllum sp. ? 
Other sections of the same formation (Sellersburg) contain Spirifer 
pennatus, Spirifer granulosus, Stropheodonta perplana, and other 
species of the Tropidoleptus fauna. Several other faunules reported 
from the southern part of the district contain Tropidoleptus; in this 
faunule it is abundant. 
As far north as Cass County traces of the same fauna are detected 
in the beds overlying the Jefferson ville limestone and underlying the 
New Albany black shales. 
Although these facts point to the presence of representatives of the 
Tropidoleptus carinatus fauna in the formation west of the ridge, it 
does not necessarily follow that the Sellersburg is the stratigraphical 
equivalent of the Hamilton formation of New York, since, as will be 
shown, the dominant as well as a large number of the ordinary 
species of that fauna appear in the Ithaca formation, known to be, 
geologically, of later age than the Hamilton formation. 
The fuller discussion of the questions here raised will appropriately 
come after the main problem is presented and elaborated, and the 
laws of shifting of faunas established by evidence. 
There will be no objection, I think, to the claim that these several 
local faunules belong to the same general Tropidoleptus fauna; but the 
formational equivalency may be questioned, as will be brought out 
as Ave proceed to the discussion of the fauna of the formations 
following the Hamilton in the eastern New York area. 
ROMNEY FORMATION IN WESTERN MARYLAND. 
Through the courtesy of the State geologist of Maryland, Prof. W. B. 
Clark, and of Prof. C. S. Prosser, the paleontologist, I am able to con- 
sult the faunule list of species from the Romney formation of western 
Maryland, recently secured under the auspices of the Maryland 
geological survey. 
In the list furnished me by Professor Prosser there appear 132 
entries, 91 of which are positive specific identifications. Among the 
latter are found all of the dominant species of the Tropidoleptus 
carinatus fauna, as estimated from the New York statistics (see Table 
V). This is sufficient to establish the extension of the Tropidoleptus 
fauna, in its integrity, as far south in the Appalachian trough as 
Maryland. 
