File:The Quarterly journal of the Geological Society of London (13889730079).jpg

THE UPPER SILURIAN OF NORTH AMERICA. 61
This rock is very nearly on the horizon of the lowest Devonian of
Europe, in which corresponding ichthyic remains are well known."
Professor Eogers goes even further and adds, " It must be enun-
ciated as a general fact that hitherto no traces have been discovered of
any vertebrate animal whatsoever during all those earlier Palaeozoic
ages which are embraced in the Cambrian and Silurian periods of the
English geologists, or the equivalent Primal, Auroral, Matinal,
Levant, Surgent, and Scalent periods according to the nomenclature
of the Pennsylvania Survey "*.
To reconcile these quotations is difficult. Professor Rogers could
not well have forgotten seeing fish-scales in the Scalent and Surgent
groups had he really done so. Such forgetfulness would be especially
difficult to one who believed that even in Europe no fish-remains of
that date were known. Sir Charles Lyell's character for accuracy is
too well known to need assertion. It is possible that Professor Eogers
saw the scales, for they were there. It is also possible that Sir C.
Lyell's memory was at fault. Altogether it is a rather singular
example of divergence between the statements of two eminent
geologists.
Description of the Species.
Onchtjs pennstlvanictjs, sp. n. (Eig. 5.)
Spine, when complete, about half an inch long, with a diameter
at base of about one eighth of an inch, very slightly curved and con-
sisting of an inner core (perhaps only composed of material filling
an original cavity) and an outer sheath. The outer portion shows
a fluted surface, with eight ridges in the quarter of the circumference
which is visible ; ridges rounded, their height being about half their
breadth ; the furrows between them acute at base and formed merely
by the edges of the two ridges without any breadth.
Locality and horizon. Perry county, Pennsylvania, in the Bloom-
field Sandstone or uppermost member of the Onondaga Yariegated
Shales.
Eig. 5. — Onchus pennsylvaui- Fig. 6. — Onchus clintoni.
cus, showing fluted surface
and core.
Onchus clintoni, sp. n. (Eig. 6.)
Spine slightly curved, the part visible about half an inch long and
showing on the one side 5 rounded low ridges meeting each other

• This statement appeared in 1858.