THE CARBONIFEROUS DISTRICT OF COLCII1.su. i: am. HANTS. 283 



not resemble the so-called Sab-Carboniferous limestones and fossils of 

 the Western States, but arc more nearly allied to those upper members 

 of the Carboniferous known in the west as lVnno-carbonifcrous. Dr 

 berry and Mr Meek, to whom specimens have been shown by Mr 

 Hartt, were much struck by these differences and resemblances; and 

 the latter suggests the idea that we may here have what M. Barraudc 

 wmihl call a "colony " of Permian forms In the Carboniferous age, — a 

 tion which contains the germ of the true solution. This same 

 solution, in another form, is also indicated in the following extract 

 from Mr Davidson's paper in reference to the remarkably rich shell 

 limestone of Brookfield : — 



-•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. Duncan, and by him made known to Dr Dawson. 



It is in the line of strike of the Shubcnacadie beds, and is doubtless a 



BOntinuation of them. This rock has such a great general resemblance 



t.. ci rtain Permian shelly limestones with which I am acquainted, 



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 Permian or a 



Carboniferous rock and its fossils; and, indeed, when M. de Vcrneuil 



determined these fossils for Sir C. Lyell in 1845, he enumerated, 



among others, Terebratula elongata and T. suftlata, Schl., Spirifera 



crutata, Schl., Avicula 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 



1 >:i\\ -mi, 1 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 



ult (of considering the rocks in question as the equivalents in age of 



the Permian of Russia) will surprise 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 Permian or Magnesian limestone forms, are enumerated.' " 



I venture to give the explanation of the whole difficulty in the 

 following statements, the illustration of which must be sought in the 

 descriptions of these rocks in other parts of this work : — 



(1.) The faunae of the seas of the Lower Carboniferous, Coal 

 formation, and Permian periods, both in Europe and America, present 

 so peal similarities that they may, in a broad view of the subject, be 

 regarded as identical. 



