xxii PERMIAN FOSSILS. 



in England, Germany, and Russia ; while others appear to have been more local in 

 their habitat, as ScJdzodus truncatus, 8. obscurus, Edmondia Murchisoniana, and Cardio- 

 morpTia modioliformis — English species ; Cardiomorpha Pallasi, and Monotis Kazanensis 

 — Russian species. Some of the above are limited in their vertical range ; while a few, 

 such as Pleurophorus 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, Solemya 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 Plenrophorus 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 Chiton Loftusianus, 

 hitherto only found in England. This species constitutes an important member, by 

 which the great hiatus between the Palseozoic 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 indicate that the conditions of the Permian ocean were not altogether 

 favorable for them. The genera Maerocheilus 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 TurHos 

 and Rissoas found in the Manchester Marls, that species became more and more 

 dwarfed as this period approached its termination. Pleurotomaria 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 {Bhyncho- 

 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 AmmonitidcB 

 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 



