78 CORRELATION OF GEOLOGICAL FAUNAS. [bull. 210. 
All the 12 most dominant species of the Tropidoleptus fauna are 
present, as has already been mentioned, and besides more than 
three-quarters ( t V 8 tt) °f the total listed species are of the Tropido- 
leptus fauna. Seven of the 21 species not in the Hamilton below 
are among the dominant species of the fauna of the typical Ithaca 
formation at Ithaca. They are starred in Table XVI. Three other 
species, together with the 7 just mentioned, occur in the typical 
Ithaca and in the formation identified as Ithaca in the eastern coun- 
ties. These three species are: 
Cryptonella endora. 
Grammysia elliptica. 
Actinopteria perstrialis. 
IMMIGRANT SPECIES OF ITHACA FORMATION. 
Among the species appearing for the first time in the strata of this 
region, distinct affinities with the Iowan and related faunas are evi- 
dent. Examples are: 
Productella hallana, 
Pugnax pugmis, and 
Spirifer (Reticnlaria) Levis. 
The common Productella speciosa may belong to the same group, 
though it is possible that this is a case of direct evolution from Pro- 
din -fella spimdicosta o f the I lam i 1 ton formation . Eh ynchonella venus- 
tula (= Hypothyris cuboides) of the Tully limestone is a still earlier 
immigrant, as was shown in a paper on the Cuboides zone/' 
Orthis (Schizophoria) tuUiensis is another closely related to Orthis 
impressa of the Ithaca zone, and believed to be a variet}^ of Schizo- 
phoria si rial ul a (Schlotheim). The Goniatites are associated with the 
western typical Portage fauna, rather than with the Hamilton fauna, 
which was restricted farther east at the time of deposition of the Ithaca 
beds. This may indicate immigration, but the case is not clear from 
the evidence now before us. The Cardiolas of the Portage group at 
Ithaca and farther west in the Genesee Valley are immigrants, and 
represent the wider fauna of Europe, but, so far as known, the pres- 
ent faunas of Iowa do not contain this genus (i. e., Glyptocardia). 
The High Point fauna (as given in full by Dr. J. M. Clarke) b con- 
tains still further traces of the western Iowa Devonian fauna. 
The lower appearance of this fauna is indicated about Ithaca in the 
Ithaca formation, in which no trace of Spirifer disjunctus has been 
discovered; but in the High Point station at Naples that characteristic 
Chemung species is reported by Dr. Clarke, although I had not seen 
it when writing up the list reported in 1883. 
The faunule of the High Point station exhibits its characteristics, but 
a The Cuboides zone and its fauna: a discussion of methods of correlation: Bull. Geol. Soc. Am., 
Vol. I, 1890, pp. 481-501. 
&On the higher Devonian faunas of Ontario County, N. Y., by J. M. Clarke (chapter on fauna 
of Chemung beds at High Point, pp. 72, etc.): Bull. U. S. Geol. Survey No. 16, 1885; see also 
Am. Jour. Sci., 3d series, Vol. XXV, Feb., 1883. 
