Professor A. Eaton, in his Geological Text Book, has proposed the
Genus Nuttainia, to include two remarkable trilobites which could not
properly be arranged in any of the previously established genera. The
two fossils here grouped together, bear no generic relation to each
other. The first species which he calls N. Concentrica, belongs to the
genus Cryptolythus, which was proposed before the appearance of his
work, and has therefore been noticed in another place.
The genus Nuttainia is thus characterized by its author: "Head in
three lobes, the middle one most prominent; the two lateral lobes
sub-hemispherical, or sub-quadrantal; the whole head bordered
anteriorly with a punctured fillet; body distinctly three lobed, middle
lobe sub-cylindric, and not so broad as the side lobes."
Nuttainia Sparsa. _Eaton._ Cast No. 35.
Fillet nearly straight in front of the middle lobe of the head,
punctures of the fillet scattered irregularly, without any alternating
ridges; head compressed, covered with scattered punctures, having its
side lobes much smaller than the middle one; middle lobe with straight
sides, giving it somewhat the form of a parallelogram.
Found in third grauwacke,[47] or grit slate in Coeymans, sixteen miles
south-west of Albany. I have the head of one before me two and a half
inches broad, and one and a half long. The whole of the animal must
have been six or seven inches in length.
[Footnote 47: In a manuscript note, Professor Eaton states that the
third grauwacke, or grit slate of Coeymans, "_alternates_ with the
underlaying cherty lime rock." This opinion some of our geological
friends, familiar with the formation at Coeymans, and with the
Professor's nomenclature of rocks, have called in question.]
The above account is copied from the "Text Book." Mr. Eaton was kind
enough to lend me the only specimen of this curious fossil remain,
which has yet been found; from which his description was taken, and of
which our cast is an exact copy. His generic characters do not in our
opinion at all apply to this fragment. Nothing but the head of this
singular trilobite remains, and it is doubtful whether what is said
to be the punctured fillet, "nearly straight in _front_ of the middle
lobe," be not the commencement of the articulations of the abdomen. The
whole fragment looks very much like the head of some large Asaph or
Ogygia.