of Nova Scotia* 137 



allied to R. Wilsoni, R. neglecta, Atrypa reticularis,^ all 

 found in the upper part of the Middle Silurian or in the Upper 

 Silurian elsewhere in America. Most of the other forms are new 

 species, descriptions of which will be found in Prof. Hall's paper 

 appended to these notes. The general assemblage is on the whole 

 like that of the Clinton, but is of such a character as to warrant 

 the belief that we may have in these beds a series somewhat 

 higher in position, and probably of Upper Silurian age. The new 

 species Chonetes Nova-Scotlca is very characteristic of the 

 upper member. 



On the whole we must regard the Arisaig series as representing 

 the upper part of the Middle Silurian, probably with a part 

 of the Upper Silurian, a position much lower than that assigned 

 to it in my Acadian Geology, which was, however, at the time, 

 based on the opinions of the best palaeontologists who had examined 

 specimens from these rocks. Unfortunately the Arisaig series 

 stands alone, wedged between carboniferous and plutonic rocks, so 

 that no opportunity occurs on the coast of verifying these conclu- 

 sions derived from fossils, by the evidence of stratigraphical con- 

 nection with newer or older Silurian deposits, and I have been un- 

 able to devote sufficient time to this object to attempt to trace the 

 beds in their succession or continuation inland. 



V 



East River of Pictotj. 



The next example of fossiliferous Silurian rocks known to me 

 is on the east branch of the East River of Pictou, and its vicinity, 

 where these deposits rise from beneath the lower carboniferous 

 series, forming the high ground on the eastern side of the river. 

 The beds are here much altered and penetrated by igneous dykes, 

 and are vertical, with very high southerly dips and N. E. and S. 

 W. strike. They consist of coarse slates and calcareous bands 

 resembling those of the upper Arisaig series in mineral character, 

 and holding many of the same species, especially Chonetes Nova- 

 Scotica ; but we have here in addition a great bed of fossiliferous 

 peroxide of iron, in some parts forty feet in thickness, and with ooli- 

 tic structure ; but passing into a ferruginous sandstone, and associ- 

 ated with slate and quartz rock. The age of these rocks relatively 

 to the Arisaig series, it is not easy to determine. The stratigraphi- 

 cal evidence, though obscure, would place them in a higher position. 

 The fossils are in a bad state of preservation ; but in so far as 



* Also Strophomena corru§ata. 



