14 THE CANADIAN NATURALIST. [Vol. ix. 



account for his opinion, and as the specimens in my possession 

 seem to contradict the greater age assigned to the rocks, I have 

 not ventured to adopt that opinion — though, up to this time, 

 without taking any notice of Dr. H.'s references to my supposed 

 mistake.* 



Another point in which I find I am at issue with Dr. H. is 

 the age of the great iron ore bed of " Webster's " or " Bhmch- 

 ard's " on the East River of Pictou, and which also has been 

 traced to the eastward in Merigomish. This I have assigned to 

 the Lower Helderberg on the evidence of stratigraphy and fossils. 

 ■Of the latter large collections have been made by Mr. D. Fraser 

 and myself in connection with the recent explorations of these 

 ores. They appear to be of unequivocal Upper Arisaig facies, but 

 include many new and interesting forms which I had hoped to 

 have described ere this time, but this has proved absolutely im- 

 possible from want of leisure. They may represent a special hori- 

 zon in the Upper Arisaig, or even between the upper and lower 

 members, or their peculiarities may be the result of local condi- 

 tions of deposit. Dr. H. seems to affirm that this iron ore is of 

 the same age with that of Nictaux, and that both are of the age 

 of the Clinton or Medina sandstone. Neither of these positions 

 can be correct, for the fossils of the East River hematite seem 

 closely related to those of the typical Upper Arisaig series, 

 while those of the Nictaux ores are, as already shewn, newer 

 than the Upper Arisaig. These two great deposits of iron ore 

 are therefore not of the same age, and neither of them can be as 

 old as the Clinton. Dr. H. correlates them with the Clinton 

 ore-beds of the United States, but he omits to notice that there 

 are also ore-beds in the Helderberg series of that country. 

 I should not, indeed, be surprised were some of the newly 

 opened beds at Nictaux, which I have not seen, to prove of 

 Helderberg age, or were beds of Oriskany age to be found at 

 Pictou. It is probable, however, that these ore-beds are less 

 constant than some of the strata associated with them. 



* It is to be observed here that the relations of the genera Petraia 

 and Zaphrentis are not so clearly defined as they should be. Some 

 palaeontologists of eminence reject Petraia altogether, and unite these 

 corals with Cyathophyllum, and the limits of the genus Zaphrentis are 

 xlifferently understood by difierent authorities. Still there are certain 

 forms, by whatever name known, which are, in our American geology, 

 characteristic of certain foiniations, and it is by this indication thai 

 I 1/ave been guided in this case. 



