distributioD of the strutu oootuiuing the bedded iron ore», iDdi- 

 oating approximately the diineDsioDH and direction of the troughs 

 resting on the Cobcquid series, and the distribution of those 

 which flunk that series on the north-east. More especi.illy these 

 researches have shewn that there are two distinct beds of iron 

 ore, separated by a considerable thickness of slaty and quartzose 

 strata,^ and underlaid by slate, sandstone, and conglomerate or 

 breccia, differing from those of the Cobequid series. I do not 

 propose here to enter into the dettiils of these observations, but 

 merely to notice their relations to the palaeontology of the district. 



The fossils collected in the district were obviously referable to 

 the " Arisaig series," ranging from the Clinton to the Lower 

 Helderberg inclusive, but tlie new facts indicated in Mr. Gilpin's 

 manuscript map, which he has kindly communicated to me, 

 suggested more careful local comparisons ; and as my collections, 

 though extensive, had not been made with reference to the now 

 details of distribution, I thought it desirable to supplement them 

 with additional material. This was obtained by Mr. Donald Fraser 

 of Springville, a well known explorer of the.se rocks, who by my 

 request visited all the exposures oi' the iron ores, and collected 

 the fossils found in the ore itself and the including beds, keeping 

 the specimens from each locality separate. In this way a large 

 number of additional specimens were obtained, forming a series 

 of local collections representing the different ore horizons. 



The general result of the study of these specimens is to .show 

 that both beds of iron ore are Upper Silurian, and approximately 

 of Lower Helderberg ag As compared with the typical Arisaig 

 series, as defined in Acadian geology, they represent the middle 

 and upper part of that series. 



The fos.sils referred to are unfortunately not always in the 

 best state of preservation. They are contained in hard rock, 

 from which they are extracted with difficulty, and are often best 

 studied in the impressions left when they arc weathered out. 

 They arc also not infrequently distorted. For these reasons it 

 is not always possible to be certain as to their identification ; 

 and in cases of doubt I have given a reference to the known 

 species which they most nearly resemble. 



* In a work on the "Mines and Mineral Lands ol' Nova SLotia," 

 received while this paper was in the press. Mr. Gilpin estimates the 

 thickness of intervening heds at 700 feet. 



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