OF DENISON UNIVERSITY. 
51 
similar lithologically, though including representatives of all the ep- 
ochs from the Hamilton to the Chester or St. Louis. The evidence 
upon this question will be given at length in the sequel. Using the 
provisional divisions of the Waverly as suggested in our earlier discus- 
sion of this group we find the distribution of species in Ohio as follows ; 
Upper division (carboniferous), Phillipsia merainacerisis, P. serraticau- 
data, sp. n., Phillipsia, sp. n. (closely related with P. auriciilatus,) 
Phaethonides occidentalis, sp. n., and Phaeihonides immaturus, sp. n. 
In division II, or that consisting of the freestone of central Ohio 
and the adjacent shales, we have thus far but the single species, Phil- 
lipsia auriculata (=rProetus missouriensis) while in division I, embrac- 
ing the lower and larger portion, we find Phaeihonides spinosiis n., 
Phillipsia (?) consors, sp. n., P. lodiensis, Meek? Proetus prcB cursor, 
Herrick, Proetus minutiLs, sp. n. , and Proetus sp. ?, as well as near the 
top P. auric Ilia tus. Tims in the lowest member the genera Proetus and 
Phaethonides predominate and the species referred to Phillipsia are at 
least closely related to Proetus and are of a Devonian rather than a 
carboniferous aspect. The middle division introduces no new ele- 
ment while the upper contains true Phillipsias as well as species of 
Phaethonides nearly allied to the carboniferous genus Brachymetopus. 
So far then as the distribution of the trilobites is concerned all facts 
sustain the conclusions elsewhere expressed as to the Devonian affini- 
ties of the faunae of the two lower members. We add descriptions of 
the species. 
Genera Phillipsia and Proetus. 
r 
While extreme examples of these genera as now understood are 
readily distinguished, they merge imperceptibly into each other, mak- 
ing the task of separating the allied forms very difficult. If one relies 
solely on the number of thoracic segments the resulting assemblages 
will be otherwise inconsistent not to mention the practical difficulty 
that, as the complete thorax is rarely preserved, we are forced in prac- 
tice to depend on characters of pygidium and head. If it could be 
agreed to limit the genus Proetus to forms like P. bohemicus, Corda, 
the problem would be more simple. We append the diagnoses of the 
genera in parallel columns. 
