252 CONTRIBUTIONS TO CANADIAN PAL/EONTOLOGY. 



C arcticum, and the Spirifcra concentrica of the sume /.one and locality, 

 by the ^//ij/ri.s;:»ar('Mto of the Athabasca, which i» little more than a 

 diminuti-ve race of S. concentrica. 



Prof Williams correlates the Ouboidcs /one of Europe with the 

 Tully Limestone of the State of New ^ork, together with certain 

 " whaly strata Beveral hundred feet above it." He suggests also that 

 " if we wish to express ])reciHe correlation in our classification of Ame- 

 rican rocks, the line between middle and upper Devonian foi'mations 

 should be drawn at the base of the Tully Limestone, to correspond with 

 the usage of French, Belgian, German and Eussian geologists, who in- 

 clude the Fra&nien, Ouhoides Schichten, and correlated zones in the upper 

 Dev(jnian." For comparison with the fauna of the Cuboides Zone in 

 Europe, Prof Williams says that '' the more important species in the 

 Tully Limestone of New York are the brachiopods, of which he gives 

 a list of thirteen. Of these, Chonetes Logani, var. Aurora, P?'oductella 

 spinuUcosta, Strophodonta perplana, Spirifera tullia, Cyrtina Samiltonen- 

 sis, Atrypa reticularis, Atrypa aspera and Bhynchonella venustula (cubo- 

 ides) occur also in the Devonian of the Mackenzie River district. The 

 large variety of Orthis TulUensis, from tlie Tully Limestone, figured by 

 Prof Williams, also, is practically indistinguishable from some of the 

 specimens of 0. striatula from the Athabasca Rivei', Hay and Peace 

 Elvers. 



The occurrence of two specimens of Strimjocephalus Burtini, asso- 

 ciated with several examples of Rensselaeria Iwvis, Meek (not Hall), 

 and the apparent absence of Spirifera disjuncta, at the " Eamparts," on 

 the Mackenzie Eiver, are, doubtless, I'ather suggestive of the " Stringo- 

 cephalus limestone," but nearly all the other species found at this 

 locality arc characteristic of the Cuboides Zone as developed in Europe, 

 or of its American representative the Tully Limestone. 



Finally the following table has been prepared to shew the close re- 

 semblance which the fauna of the Devonian rocks of the Mackenzie 

 Eiver district, as exemplified in these pages, bears to that of the same 

 formation in Europe or upon the European side of the Atlaotic. 



Mackenzie River District. Europb. 



Aulopora serpens. Aulopora serpens. 



Cyathophyllum arctioanj. Cyatljophyllum hexagonum. 



Cyathopbyllum ctcspitosum. (Cyathophyllum ciespitoaum. 



Cyathophyllum Athabascensis. Cyathophyllum ceratites, Goldfuss. 



Campophyllum elliptioum. Campophyllum Seetenieum, Scbluter. 



Phillipsastnra Hennabi. PhillipsastriPa Hennahi. 



Pachyphyllum Devoniense. raohypbyllum Devoniense. 



Pachypora cervicornis. Pachypora uervicornis. 



