In the vast quarries of slate at Angers, in France, there is frequently
noticed two very remarkable organic remains, which have for a long
time excited the attention of naturalists. To receive these curious
relics, Professor Brongniart established the genus, Ogygia, which he
thus characterizes. Body much depressed--elongated into an ellipse,
terminated in points--nearly equal at its extremities, and not capable
of contracting itself into a spherical form. The buckler is bordered by
a slight longitudinal furrow, rising from its anterior extremity, and
its posterior angles terminating in elongated points. The abdomen has
eight articulations, and its longitudinal lobes are not very prominent.
The eyes are neither prominent nor reticulated and there are no other
protuberances on the buckler.
In Professor Brongniart's original work on the Trilobites, he has
described the two specimens from Angers, under the specific names
of Guettardi, and Desmarestii, in compliment to M. M. Guettard and
Desmarest; and in De La Beche's Manual of Geology, we are informed that
he has since identified two other species; one of which is supposed to
be found in North America; this he calls _Ogygia Sillimani_; the banks
of the Mohawk River, near Schenectady, is the locality from which it
is said to have been derived.
As we have not been able to find any detailed account of this species,
we have admitted both it and the genus to which it is said to belong
into our Monograph exclusively on the high authority of Professor
Brongniart, as quoted in the Manual of Geology. We are not ignorant of
the species of Trilobites found near Schenectady, and if permitted to
offer a suggestion on this subject, it would be, that the description
of the American ogygia, was made out by its distinguished author from
the fragment of an Isotelus. The Isotelus is not uncommon in that
vicinity, and one of its extremities might, even by a very close
observer, be mistaken for that of an Ogygia--especially by those who
are not perfectly familiar with the Isotelus.