44 PROCEEDINGS OF THE NATIONAL MUSEUM. vou. xxxuv. 
those forms which have a different distributional or range value are 
removed and redescribed under a separate specific name. 
The following-named specific groups are sufficiently well restricted 
in either their geographic distribution or geologic range to serve a 
useful purpose in the indication of geological horizon: 
Dalmanella leonensis Hall, 1867. This species appears in the 
Chemung formation of Chautauqua and Cattaraugus counties, and ~ 
extends as far eastward as the Genesee Valley. It ranges from the 
earliest appearance of the typical Chemung fauna upward, but the 
limit of its upward range is not known to the writer. 
Dalmanella danbyi, new species, appears in the Danby Dalmanella 
zone at the base of the Chemung formation in Schuyler, Tompkins, 
Chemung, and Tioga counties of central New York. It is restricted 
in range to the lowest 150 feet of the Cayuta member of the 
Chemung, that is, the Dalmanella danbyt zone. 
Dalmanella superstes Hall and Clarke, 1892, associated with D. 
danby?, is found in the Dalmanella danbyi zone at the base of the 
Chemung in Steuben, Chemung, and Tioga counties. 
Thiemella villenovia, new genus and new species, is associated 
with D. leonensis in Chautauqua County, New York. 
Dalmanella tioga Hall, 1867, appears in the Cayuta member of the 
Chemung formation in Schuyler, Tompkins, Chemung, and Tioga 
counties, central New York. It is common in the lower Cayuta mem- 
ber above the Dalmanella danbyi zone but it 1s not common above 
the niddle of that member. 
Dalmanella elmira, new species, appears in the Cayuta member of 
the Chemung formation in Chemung nd Tioga counties; is common 
throughout the Cayuta member above the Dalmanella danbyt zone, 
but is rarely if ever seen in the Wellsburg member. 
Dalmanella carinata Hall, 1848, appears in the third Tropideleptus 
zone and the upper part of the Cayuta member of the Chemung 
formation of Chemung and Tioga counties, central New York. 
Dalmanella allegania, new species, appears in the lower part of the 
Chemung formation at Cuba, Allegany County, where it is associated 
with Dalmanella leonensis. The limits of its range are not known. 
Dalmanella virginia, new species, appears in the Chemung forma- 
tion of West Virginia; it has not been seen in New York State. The 
hmits of its distribution and range are not known, but it is restricted 
according to present knowledge to the eastern extension of the Che- 
mung basin. : 
GHNERAL CHARACTERS. 
Examination of the Dalmanellas in their relations of distribution 
and range has made some general facts clear which may be mentioned 
before classifying them or going into details in defining their dif- 
ferences. 
