Dr. H. M. Ami — The Dicfyonema Slates of Nova 8cotia. 219 



B. Wehsteri have revealed remarkable and indubitable resemblance 

 and close affinity of this species with the Dictyonema flahelliforme, 

 Eichwald, which finds a synonj^m in the I), sociale of Salter, 

 a characteristic Upper Cambrian form. 



In comparing the microscopical characters of the rhabdosome of 

 D. Wehsteri with those of B. flabeUiforme, Eichwald, especially as 

 they are presented and illustrated in Carl Wiman's classic work,^ the 

 peculiar rope-like structure of the polypary is clearly discernible, 

 so that there is practically no doubt as to the identity of the two 

 species. 



It will therefore now be necessary to refer D. Wehsteri as 

 a synonym of D. flahelliforme, Eichwald, and to refer the Kentville 

 formation, not to the Silurian (Upper) system, but to the Cambrian. 

 In fact, the slates of the Kentville formation of Kings and Annapolis 

 Counties in Nova Scotia are equivalent in age or are taxonomically 

 similar to the slates of Barachois and associated localities in the 

 Nura Series of Cape Breton, as well as to the Dictyonema slates 

 of Navy Island, near St. John City, and the slates of Eel Eiver, near 

 Benton in New Brunswick, all of which are referable to the Upper 

 Cambrian. 



The first rapprochement made by me between Dictyonema flahelli- 

 forme and D. Wehsteri took place some two years ago, when the 

 specimens of Dictyonema obtained by Professor L. W. Bailey near 

 Benton, along the Eel Eiver in York Co., N.B., were compared 

 with the specimens of D. Wehsteri at present in the collections of 

 the Geological Survey Department, and ihey were found to be so 

 closely related as not to be practically separable. From specimens 

 of D. flahelliforme obtained on Navy Island, kindly loaned to me 

 for study and reference by Professor Bailey of the University of 

 New Brunswick, it was readily seen that the Benton specimens 

 were identical and therefore of Upper Cambrian age. 



In order to ascertain definitely whether D. Wehsteri, Dawson, from 

 New Canaan, was identical with D. flahelliforme, the type-specimens 

 of the former, which formed part of the Dawson collections in the 

 Peter Eedpath Museum of McGill University, were kindly loaned 

 to the writer by Professor F. D. Adams. These are preserved on 

 two slabs of more or less hardened red shale or slate, and scattered 

 over the surface of the slates in a rather poor state of preservation, 

 except in one case from which very probably the illustration 

 (fig. 196) on p. 563 of the "Acadian Geology " was prepared. 



The writer is satisfied that the upper beds of the Cambrian are 

 thus represented in that portion of Nova Scotia by the Dictyonema 

 flahelliforme beds at Kentville, New Canaan, and the Gaspereau 

 Valley, south side. 



We thus find that the zone or horizon of Dictyonema flahelliforme, 

 Eichwald, occui's at the following localities in Canada, which may 

 consequently be referred to the Upper or Neo-Carabrian : — 



^ See "Ueber die Graptoliten" : Bull. Geol. Inst. Upsala, p. 55, pi. x, figs. 13, 14. 

 Also Eichwald, " Gorqonia flahelliformis''^ : Sil. Schicht. Syst. iu Esthland, 1840, 

 p. 207. 



