76 
CORRELATION OF GEOLOGICAL FAUNAS. 
[BULL. 210. 
The first 2 species of Table XIV are still dominant in the fau- 
nule aggregate, but the other 10 species of the list have lost their 
preeminence and are replaced by other species. 
This fact will be better appreciated by examination of the list of 
species having highest distributional and abundance values in the 
Ithaca faunules. Table XV, representing collections from 67 locali- 
ties, shows the dominant species of the eastern extension of the Ithaca 
formation. Comparison of Tables XIV and XV will show how com- 
pletely the dominant species of the Tropidoleptus carinatus fauna 
(excepting the two chief species) have lost their supremacy in the 
fauna, the highest frequency value of the last 10 species of Table XIV 
appearing far below the twelfth in rank of the dominant list: 
Table XV. — Productella speciosa fauna: Dominant species of the eastern exten- 
sion of the Ithaca formation. 
1. Spirifer mesistrialis 
2. S. pennatus 
3. Tropidoleptus carinatus 
4. Camarotoechia eximia 
5. Chonetes setigerus . 
6. Paracyc-las lirata 
7. Chonetes scitulus. . . 
8. Leiorhynchus mesicostalr 
9. Actinopteria boydi 
10. Camarotcechia stephani . 
11. Pakeoneilo emarginata 
12. Cypricardella gregaria 
36 
6 
31 
4 
31 

19 
6 
20 

18 

15 

12 
o 
12 
1 
9 
3 
12 

9 
1 
24 
11) 
li) 
12 
9 
4 
9 
7 
7 
7 

4 
In the first column of Table XV is given the number of positively 
identified occurrences in (17 analyzed faunules. In the second column 
are the additional times in which the identifications are marked as 
doubtful. The figures in the third column indicate Ihe number of 
cases in which the species is marked abundant or common in the 
faunule analyzed. 
In the case of Spirifer mesistrialis the species most readily confused 
with it is S. granulosus. That species is recorded twice positively, 
with 4 questionable identifications. 
Spirifer pen mil as may be confused with S. pennatus var. posterns, 
of which 1 doubtful case is recorded, and with 8. mesicostalis, of which 
2 positive and 4 doubtful identifications occur. In 4 of the faunules 
in which the latter species is mentioned it is common or abundant. 
PRODUCTELLA SPECIOSA FAUNA. 
Iii the 67 faunules examined in this eastern region Productella 
speciosa occurs but once positively, and four times it is reported with 
