WILLIAMS 
KIN 1)1 
!e and ] correlation of catawissa section. 85 
faunas, as in the Ithaca section. The fossiliferous zone extends about 
400 feet above it in both cases; and the difference in the range of fos- 
sils, indicated by the statistics now on hand, is shown by the fact that 
in the Catawissa section such species as Spirifer pennatus v&v. posterus, 
Sch izophoria striatula, and Leiorhynchus mesicostale, appear well below 
the first Spirifer laevis zone while in Ithaca they do not appear below 
it. It is noticeable that the brachiopods dominate above while in the 
lower 200 feet of the fossiliferous zone there are few brachiopods 
though there is a sparse fauna of gastropods, lamellibranchs and 
cephalopods. In this feature the Oatawissa and Ithaca sections agree. 
This mingling of the two faunas, which are more sharply differen- 
tiated in the Ithaca section, is probably due to the geographical posi- 
tion of the section. 
In western New York, along the Genesee Valley, the interval between 
the Genesee shale and the first appearance of the Chemung fauna is 
occupied by the Nunda formation, with no trace in it of the rich 
Ithaca fauna. Very little trace of that fauna is seen in the Seneca 
Lake Valley sections, while at Ithaca there is a zone of 400 feet pre- 
ceded as well as followed by Nunda conditions and fauna. This 
zone is occupied by the rich brachiopod fauna of the typical Ithaca 
formation. 
Points to be noted in the faunal combinations are the association of 
Spirifer pennatus var. posterus with Reticularia Izevis in zone 11, and 
the appearance of the former over 200 feet lower in zone 7. Another 
interesting association is Tropidoleptus carinatus, in zone 15, with 
Productella speeiosa, Cryptonella eudora, Spirifer mesistrialis, and S. 
pennatus var. posterus. This is evidently a recurrence from the Hamilton 
formation, and is to be correlated in time with the occurrence recorded 
in the Ithaca section in Bulletin 3 (page 15) of the faunule called in 
that report No. 14 N. The species Tropndoleptus carinatus does not 
appear in the latter zone at Ithaca so far as at present discovered, 
but several common Hamilton forms do. 
From zone 26 upward for about 300 feet no fossils were detected, 
and the upper fossiliferous zone occupies the succeeding 400 feet. 
This upper zone (31-40) holds a fauna in which the dominant species 
are still those of the Ithaca beds. From 26 to 40, inclusive, may be 
correlated with the upper Nunda of the Ithaca section. 
It will be noticed that the Strop heodonta is almost completely 
absent, a single species referred to, S. demissa, appearing in both 38 
and 40. Schizophoria striatula is present, but Cryptonella is want- 
ing, as is also Spirifer mesistrialis. Pugnax pugnus and Reticularis 
Idevis are both present, the former frequently and in considerable 
numbers. Productella hallana is not recorded, but it probably would 
be found on more thorough search. These characteristics of the 
