1224 Note on some Fossil Fishes recently discovered (December, 
ers and present a beautiful spectacle with an objective of a fourth 
or a fifth of an inch. 
This description coincides in all details of importance with 
those given by Professor Huxley in his figure of Scaphaspis, 
But in several minor points of structure there are differences 
which make it doubtful if the specimens here described can be 
referred to that genus. The most conspicuous of these is the 
regularity and parallelism of the vessels in the outer layer, a fea- 
ture not shown in any already described species of Pteraspid, so 
far as I have been able to ascertain. This and some other dis- 
tinctive features have induced me to place them in a new genus 
under the name of Palzaspis, in which they constitute two 
species: Paleaspis americana’ Paleaspis bitruncata. 
Accepting the usual correlation of the Upper Silurian rocks of 
Britain and America, according to which the Ludlow rocks are 
the stratigraphic and palzontologic equivalents of the Lower 
Helderberg, the lowest bed of the latter, the Water Lime must lie 
on the horizon of the English Lower Ludlow. The last is the 
lowest fish-bearing stratum known in Europe, and has thus far 
yielded only a single specimen. This, the earliest vertebrate fos- 
sil hitherto known, is, as Lankester remarks, enormously older 
than its kindred fossils from the Upper Ludlow, the bone bed of 
which has yielded numerous specimens both of the same species 
(Scaphaspis ludensis) and of others. oa 
The fossils above mentioned were found in a stratum which, 1m 
my report on the geology of Perry county, now in the press, I 
have named the “ Bloomfield sandstone.” It lies at the top of 
the variegated shale or marl, the middle portion of the great 
mass of the Onondaga. This—the upper part of the fifth group 
of Rogers in the first survey of Pennsylvania—is about 1500 feet 
thick and almost barren of fossils. The only species, excepting 
those here described, with which I have met in the county, i 
well-known crustacean, Leperditia alta. This shale 1s div! 
into three parts: 
Lower Helderberg, water lime. 
eet. 
bon oc Se OT Oa hak eas 200 ft r 
Onondaga... 1 Var T DORE, ER coe E <2 98 88S ih 5 
ER NM E E E a ce eer ; thia d 
_ The “Bloomfield sandstone” consists of a series 0 
_and gray beds separating the variegated from the gray mar 
fossils have not been found generally diffused over the ex 
j}. The 
