96 HENRY SHALER WILLIAMS 
Strophomena delthyris (p. 258, Pl. 14, Fig. 19) =(?) Leptostrophia perplana. 
Delthyris chemungensis (p. 263) =Spirifer disjunctus. 
Atrypa chemungensis (p. 265)=Atrypa reticularis. 
In the Final Reports on Paleontology,’ a large number of species 
were added to these lists, but for the purpose of determining the 
typical Chemung fauna and settling its lower boundary these species 
should furnish conclusive evidence. Those of the list which are 
restricted in range in this original section may fairly be regarded as 
diagnostic of the Chemung formation at its typical outcrop. 
The two lists contain the following twenty species: 
. Phacops nupera (Hall). 
. Pterinea chemungensis (Hall). 
Il. 
I2. 
P. lachrymosa var. lima (Hall). 
Stropheodonta (Douvillina) 
muconata (Vanuxem)- 
3. Leptodesma spinigerum (Conrad). 13. Leptostrophia (? perplana) 
4. L. protextum (Conrad). delthyris (Conrad)- 
5. Avicula multilineata (Conrad). 14. Dalmanella carinata (Hall). 
6. Goniophora chemungensis 15. Dalmanella tioga (Hall). 
(Conrad) 16. Spirifer disjunctus (Sowerby). 
oOo own 
. Mytilarca chemungensis (Conrad). 
. Schizodus chemungensis (Conrad). 
. Orthothetes chemungensis (Hall). 
Io. 
Productella lachrymosa (Hall). 
. Spirifer mesistrialis (Hall). 
. Delthyris mesicostalis (Hall). 
. Atrypa spinosa (Hall). 
. Atrypa reticularis (Linn). 
Of these species No. 1, Phacops nu pera, is a variety of the common 
species P. rana, if not identical; but it was obtained from a loose 
block, as we are told in Paleontology, Vol. VII, p. 27, so that it is 
not certainly a part of the original Chemung fauna. 
No. 5, Avicula multilineata, is not referred to in later literature, 
and for correlation purposes it is too rare to serve as a diagnostic 
species. 
No. 8, Schizodus chemungensis, is reported as from “near Ithaca 
and Cortland,’’? and as the rocks of these localities are now known 
to lie at a horizon lower than the rocks of Chemung Narrows, the 
species ceases to be diagnostic of the latter formation. 
No. 9, Orthothetes chemungensis, as a species has a considerable 
range: it is quite variable in its Chemung expression, so that the 
name without restriction will not constitute it a diagnostic species 
of the Chemung. 
t Paleontology of New York, Vols. IV, V, VI, VII, and VIII. 
2 Paleontology of New York, Vol. II, p. 454. 
