DEVONTPAN, SECLION@“OF TRAACA, IN. Y. 97 
No. 13, called Strophomena delthyris by Conrad, is quite distinct 
from the form described by the same name under the name Siroph- 
omena perplana to which it has been referred by Hall. If it be a 
variety of Sir. perplana Conrad, it is sufficiently distinct to receive a 
distinct varietal name, and then will appear as Leptostrophia per- 
plana delthyris (Con.). 
Hall did not recognize the species called by him Strophomena 
nervosa? as coming from the Chemung Narrows section; nor does 
he list it from that section in the final description of the variety.? 
It may therefore be discarded from a strictly diagnostic list. 
No. 17, Spirifer mesistrialis, in the final description of the species 
is listed from near Cortlandville in Cortland County. The rocks 
there exposed are stratigraphically at a lower horizon than Chemung, 
so that the species will not serve to settle the question as to whether 
the Chemung fauna is or is not identical with that of the Ithaca 
member. 
No. 18, Delthyris mesicostalis Hall. ‘This species was described 
from a specimen from Angelica, N. Y., and was not reported by 
Hall from the Chemung Narrows section. ‘The form which has later 
been identified as of this species, was originally described as Del- 
thyris acuminata by Hall; this specific name was dropped because 
it had already been used by Conrad for a Spirifer. This latter form 
was recognized by Hall as coming from Ithaca, and Cayuta Creek. 
This form (referred to by Hall under the name Delthyris acumt- 
nata) is a common Chemung species; but the discovery of its inti- 
mate association with the Tropidoleptus fauna, its close affinity with 
Delthyris consobrinus (also a Hamilton species), and its occurrence 
in the Van Etten and White Church zones of Tropidoleptus entirely 
below the range of Spirijer disjunctus, the Dalmanellas, the Dou- 
villinas, and Plerinea chemungensis, has led me to believe that it 
does not belong to the typical Chemung fauna, any more than do 
Tropidoleptus carinatus and Rhipidomella vanuxemi, both of which 
are abundant in some zones of the section at Chemung Narrows. 
Independently, therefore, of the question as to whether there is 
t Final Rept. Fourth Dist. (1843), p. 266, Fig. 1. 
2 Paleontology, etc., Vol. IV, 113, 114. 
3 Report Fourth Dist. N. Y. (1843), p. 271. 
