WILLIAMS.] 
FAUNAL DISSECTION OF THE DEVONIAN. 
51 
large set of local faunules, prepared in determining, by the fossils, 
the areal distribution of the formation, has been examined, and only 
those faunules were taken which hold accredited Hamilton species. 
In order to obtain evidence as to the composition of the fauna in 
different parts of its history, a complete series of the faunules of each 
fossilif erous zone from bottom to top of a t3 T pical section of the forma- 
tion was examined, and the proportionate abundance of species for 
each zone and the range of the species were thus ascertained. 
TROPIDOLEPTUS CARINATUS FAUNA AS EXPRESSED IN EASTERN COUN- 
TIES OF NEW YORK AND PENNSYLVANIA. 
An examination of the faunal lists prepared by Prof. C. S. Prosser a 
for the eastern counties of New York and Pennsylvania furnishes 146 
localities from which fossils of the Hamilton formation have been 
carefully collected and listed. In all 172 species were positively 
identified. The localities are distributed over the counties of Madi- 
son, Chenango, Broome, Otsego, Delaware, Schoharie, Albany, Greene, 
Ulster, and Orange, of New York; and Pike, Monroe, and Carbon, of 
Pennsylvania. The species listed in these tables have been tabulated 
so as to exhibit the number of times each species is recorded in the 
separate faunules. The abundance or rarity of each species in the 
particular faunule was also recorded. 
From this complete tabulation of the statistics the following table 
has been prepared to show the species which stand highest in respect 
to frequency of appearance in the faunules of the region studied. 
Table I. — Tropidoleptus car inatus fauna: Species occurring most frequently in 
the Hamilton formation east of Cayuga Lake. 
[Dominant distributional frequency list for eastern New York.] 
1. Spirifer pennatus 
2. Tropidoleptus carinatus 
3. Spirifer granulosus 
4. Chonetes coronatus 
5. Palaeoneilo constricta _ . 
6. Nucula bellistriata 
7. Amboccelia umbonata _ . 
8. Nuculites triqueter 
9. N. oblongatus 
10. Nucula corbuliformis . 
11. Athyris spiriferoides . . 
12. Phacops rana 
^loSlitfef Number of 
at'wnich poupsot 
found. 
113 
89 
59 
57 
56 
42 
40 
38 
35 
33 
32 
32 
localities. 
30 
27 
28 
26 
27 
23 
'J 'J 
22 
21 
L7 
24 
is 
Abun- 
dant. 
26 
22 
ll 
1() 
2 
4 
4 
1 
1 
4 
2 
1 
Common. 
33 
30 
15 
16 
5 
8 
8 
7 
3 
3 
5 
4 
a The classification and distribution of the Hamilton and Chemung series of central and eastern 
New York: Fifteenth Ann. Rept. State Geologist New York, Part 1, 1895, pp. 87-222. 
The classification and distribution of the Hamilton and Chemung series of central and eastern 
New York: Seventeenth Ann. Rept. State Geologist New York, Part II, 1900, pp. 67-327. 
The Devonian system of eastern Pennsylvania and New York: Bull. U. S. Geol. Survey No. 
120, 1894, pp. 1-81. 
