60 
CORRELATION OF GEOLOGICAL FAUNAS. 
[BULL. 210, 
In this table columns 1, 2, 3 express, approximately, in percent- 
ages, the facts shown in Tables I, II, and III; column 4 indicates 
the species which are recorded in the fauna of Ontario, Canada ; a 
column 5 gives the sum of the percentages in the first three columns, 
and column 6 shows the relative order of the species, according to 
the results thus reached. 
Tabulating the species in this order the following table is obtained : 
Table V. — Tropidoleptus fauna: Standard list of dominant species for the New 
York- Ontario province. 
1. Spirifer pennatus 
2. Phacops rana 
3. Tropidoleptus carinatus 
4. Amboccolia umbonata ... 
5. Athyris spiriferoides - . . 
6. Palgeoneilo constricta. . 
Per cent 
of bionic 
value. 
7!) 
58 
54 
17 
i:» 
7. Spirifer granulosus _ . 
8. Chonetes coronatus . _ 
9. Nuculites triqueter . 
10. Nucula corbuliformis 
1 1 . Nuculites oblongatus 
12. Nucula bellistriata . . 
Per cent 
of bionic 
value. 
36 
33 
33 
31 
20 
The figures to the right in this list express in percentage the approxi- 
mate bionic value for each of the species as obtained from the sta- 
tistics before us. It will be seen that there are 10 species which have 
a bionic value in this fauna of 83 per cent and over, and no other 
species attain this bionic value when tested by the several modes of 
estimating them which have been here defined. 
The first 10 species in this list (Table V) may be regarded as the 
10 most characteristic species of the fauna of the Hamilton formation 
as it is seen in New York State, as determined by the evidence already 
presented. 
The geographical distribution of the fauna may be recognized by 
the distribution of these species. A fauna which fails to contain any 
of them can not be said to be the Tropidoleptus fauna, although it 
may be called equivalent (on some basis) to it. 
When the vertical range of the fauna is under consideration, so 
long as a majority of these 10 species continue to appear in the rocks, 
although lithologically or stratigraphically they lie above the Hamil- 
ton formation, it will be correct to state that the fauna still lives and 
preserves its bionic integrity in the measure of dominance of these 
species. When, therefore, the question as to upward range of the 
Tropidoleptus fauna is discussed, these species should be considered 
as the standards by which the fauna is to be recognized, irrespective 
of the stratigraphical evidence of continuance or noncontinuance of 
the Hamilton formation. 
The effect of checking up the eastern list, on the basis of the vertical 
"On some additional or imperfectly understood fossils from the Hamilton formation of 
Ontario, with a revised list of the species therefrom, by J. F. Whiteaves: Contributions to Cana- 
dian Palaeontology, 1885-1898, Vol. I, Part V, pp. 361-43(5, Pis. XLVIII-L 
