Identity of Atops trilineatus with Triarthrus Beckii. 323 
committee appears in the proceedings for 1847. As truth is the 
t before us, we need offer no, apology for presenting some 
—_ of the case which have not been discussed, bearing upon 
that report. 
__ Were it even determined that these fossils from different local- 
ities, and from slates in different conditions, are different species, 
the question supposed to rest upon it, is not in our opinion at all 
ided ; for if there be so close an analogy in the genera and 
speciés of Trilobites that there is an acknowledged difficulty in 
deciding upon the difference between them, then it must be con- 
fessed that there is still less reason for the foundation of a distinct 
system of fossiliferous deposits upon this basis. 
‘ the summer of 1844, Dr. Fitch of Salem, Washington 
county, N. Y., discovered in the partially altered slates of Green- 
wich, in that county, some remains of T'ilobites, which were 
Placed in the possession of Dr. Emmons who subsequently visited 
the locality and obtained other specimens. These were pub- 
lished in his paper upon the ‘Taconic System in the same year, 
and subsequently in his Report on the Agriculture of the state, 
In 1846.* These fossils were shown to me at the time of their 
discovery, and one of them decided to be new while the other 
was unquestionably the Calymene ( Triarthrus) Becki. The 
former was published under the name of Elliptocephalus,t and 
the latter of Atops. 
In 1846, at the meeting of the Association in New York, I 
temarked, in a discussion upon the Taconic System, that the 
Atops trilineatus and Triarthrus Beckii were identical, and hence 
the reference to a committee. 
It remains now to inquire of what importance are the differ- 
ences — out, in the report of Mr. Haldeman, and whether 
these differences are actual and constant, or only accidental and 
dependent on circumstances. | 
The Calymene (Triarthrus) Beckii, was first named by Prof. 
“aton, Bronguiartia carcinoidea, from a buckler which he sup- 
posed to be the entire animal. Prof. Green followed, proposing 
the name of Triarthrus, still describing the imperfect buekler as 
the entire animal. Subsequently, Dr. Harlan, some of 
the articulations of the thorax, referred it to the genus Paradox- 
ides. The latter name was followed by myself in the American 
Journal of Science, Vol. xxxiii, p. 137, where the true characters 
Te i i ot 
* Agricul : isi account of the classification, com- 
Oo adams ghia ga’ aa gp rin and the Natural Waters of the 
different Geological Formations, together with a condensed view climate 
an agricultural productions of the State. By Esxxezen Emmons, M.D. Voli. 
any. e846. 
t Thi i j Olenus, judging from the general char- 
acter ‘essed —, “as rath . See elcentohey of atom, vol. i, 
P- 256, pl. 67, fige, D2, b,c 
Sxconp Series, Vol. V, No. 15.—Muy, 1848. 42 
