160 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jail. 7, 



hence the great local diversity. He is, moreover, inclined to con- 

 sider that in each locality the " Lower Limestones " are darker in 

 colour, more laminated, and less fossiliferous than the upper ; also 

 that the individual beds become darker, more impure, and less fossili- 

 ferous as they approach the high lands which formed the old shore- 

 lines ; but that there are, of course, exceptions to these statements. 



The very remarkable shell-rock above described occurs at Brook- 

 field, a little east of the Shubenacadie River ; it was first discovered 

 by the late Mr. G. Dunkin, and by him made known to Dr. Dawson. 

 It is in the line of strike of the Shubenacadie beds, and is doubtless 

 a continuation of them. This rock has such a great general resem- 

 blance to certain Permian shelly limestones, with which I am ac- 

 quainted, that, had the specimens been submitted to me without any 

 indication as to their geological age, I should certainly have felt 

 somewhat puzzled to determine whether I had to deal with a Per- 

 mian or a Carboniferous rock and its fossils ; and, indeed, when M. 

 do Yerneuil determined these fossils- for Sir C. Lyell in 1845, he 

 enumerated, among others, Terebratula elongata and T. sufflata, 

 Schl., Spirifera cristata, Schl., Avicilla antiqua, Minister, a Modiola, 

 a Littorina, and one or two other fossils which he considered to be 

 common to both the Permian and the Carboniferous strata. Although 

 I may modify to some extent the lists of species published by Sir C. 

 Lyell and Dr. Dawson, I quite coincide with what is stated by the 

 former author, at p. 205 of his ' Travels,' viz., " That geologists 

 should at first arrive at this result (of considering the rocks in ques- 

 tion as the equivalents in age of the Permian of Russia) will sur- 

 prise no one who is aware how many of the fossils of our Magnesian 

 Limestone and Coal resemble each other, or who studies the lists 

 given at p. 218, in which several species both of shells and corals 

 from Nova Scotia, identical or closely allied to well-known Per- 

 mian or Magnesian Limestone forms, are enumerated." 



This is important to note : for it was written in 1845, just at the 

 time the celebrated authors of the great work on Russia in Europe 

 and the Ural Mountains (published in 1845) arrived from that 

 country ; and it denotes how strongly impressed they were that a 

 certain number of Carboniferous species had continued to exist 

 during the Permian period. Subsequent researches have confirmed 

 this view, and considerably multiplied the number of species common 

 to the two epochs ; and it has been proved in the most satisfactory 

 manner that the Permian formation is the natural continuation of 

 the great Carboniferous system, of which it composes the upper 

 portion, although it is desirable to distinguish the group by the 

 separate designation of " Permian." It is not the Mollusca and 

 Plants of the Permian period alone which, as M. Marcou supposes, 

 have a Palaeozoic aspect, but, as M. de Yerneuil *, Mr. Kirkby t, and 

 others have already shown, the whole bulk of the animal and 

 vegetable remains found in the Permian rocks bear the most unmis- 

 takeable Palaeozoic stamp. But, again, it would be fallacious to 



* Bulletin de la Soc. Geol. de France, 2 e ser. vol. xix. pp. 599, 627 (1862). 

 t Annals and Mag. Nat. Hist. 3rd Series, vol. x. Sept, 1862. 



