Xx PERMIAN FOSSILS. 
in England, Germany, and Russia; while others appear to have been more local in 
their habitat, as Schizodus truncatus, S. obscurus, Hdmondia Murchisoniana, and Cardio- 
norpha modiolifornis—English species ; Cardiomorpha Pallasi, and Monotis Kazanensis 
—Russian species. Some of the above are limited in their vertical range ; while a few, 
such as Plewrophorus costatus, &c., adding Leda Vinti, characterise the three highest 
members. And it is remarkable, that those species which are suspected to have 
carboniferous representatives, are such as have the most extensive chronological and 
geographical range: for example, So/emya biarmica, which occurs nearly wherever the 
Permian system is developed, is found in the Kupfer-schiefer of Ilmenau, and in the 
fossiliferous limestone of Durham; and Pleurophorus costatus, equally as extensively 
distributed geographically, has probably been found in the lowest Permian member, 
that is, in a bed of limestone between the Weissliegende and Kupfer-schiefer, and in 
the highest beds of the system—the Marls near Manchester. Some genera, which are 
extremely abundant in later periods, seem to have commenced their existence during 
the Permian epoch: the Russian Ostrea matercula,-De Verneuil, the most anciently 
known species of the genus, is exceedingly interesting on this account. 
The Gasteropods of the Permian period are not quite so numerous as the last 
class; and the principal point of interest connected with them is in Chzton Loftusianus, 
hitherto only found in England. This species constitutes an important member, by 
which the great Azatus between the Paleozoic and existing species of the genus is becom- 
ing gradually filled up. One remarkable circumstance connected with the Permian 
Gasteropods is their general diminutiveness, which, coupled with their scarcity, 
seems to imdicate that the conditions of the Permian ocean were not altogether 
favorable for them. The genera Macrocheilus and Pleurotomaria, which had some 
splendid and noble representatives during the earlier. periods, became impoverished, 
as it were, in the Permian: and it would appear, from the size of the so-called Turbos 
and Rissoas found in the Manchester Marls, that species became more and more 
dwarfed as this period approached its termination. Plewrotomaria nodulosa seems to be 
limited to England, and P. penea, to Russia. The genus Murchisonia, represented by 
M. subangulata in the Permian rocks only of Russia and Germany, would appear to have 
occurred for the last time during this period. : 
Nothing higher than the Tetrabranchiate section of the Cephalopods has yet been 
found in Permian strata; though, from the presence of Cuttle-fish mandibles (Rhyncho- 
lithes), and some other co-ordinate remains, in deposits of the Triassic system—perhaps 
the earliest in which anything of the kind has yet been found—we ought to be prepared 
for the occurrence of the Dibranchiate section. Considering the abundance of 
Goniatites in the Carboniferous rocks, and the presence of the remarkable genus 
Ceratites in the Triassic system, it is singular that no remains of the family Ammonitide 
have yet been found in the Permian deposits, especially, considering that the genera 
named are completely graduated into each other by means of the transitional group 
