418 THE CANADIAN xNATURALIST. [Vol. vii. 



the Cretaceous ao-e of some beds associated with the coals and 

 lignites or immediately underlying them ; and whether the lig- 

 nite beds themselves are to be placed in the Miocene, as New- 

 berry and Heer decide from their fossil plants, or as others hold 

 from their animal forms in the Lower Eocene, or even Upper 

 Cretaceous, it is clear that no decided break either iu life or 

 physical conditions separates them from the upper Mesozoic. 



In another field, Dr. Harrington's Report, though chiefly 

 practical, is not without features of scientific interest, more 

 especially as to the mode of origin and metamorphism of iron 

 ores. The following extract may serve as an illustration : 



" Concerning the origin of our sedimentary magnetites, the 

 question arises as to whether they were originally deposited as 

 such, or in some other form, and afterwards altered to magnetite. 

 It seems possible that, in some cases, beds may have been 

 formed by the accumulation of iron sands, just as they are form- 

 ing in the Gulf of St. Lawrence to-day, the material being 

 derived from the disintegration of pre-existing crystalline rocks. 

 Such beds we should expect to contain not only magnetite, but 

 ilmenite, and it is well known that in many cases ores on being 

 pulverised may be more or less completely separated into a mag- 

 netic portion containing little or no titanic acid, and a non- 

 magnetic portion consisting essentially of ilmenite. It seems, 

 however, probable that iu general their origin has been similar 

 to that of the modern bog and lake ores. Deposits of magnetite, 

 as a rule, do not continue of uniform thickness for any great distance 

 like the enclosing rocks, and this is just what might be expected 

 if we suppose them to have originally occurred as bog or lake 

 ores which accumulated in local hollows or depressions. No ore, 

 moreover, would be more readily converted into magnetite than 

 bog ore, on account of the considerable proportion of organic 

 matter which the latter contains." 



" In this connection may be described a very simple but inter- 

 esting experiment tried with a specimen of bog ore from L'Islet, 

 containing about 22 per cent, of water and organic matter. The 

 pulverized ore was placed in a platinum crucible, and heated for 

 an hour at a temperature of 190*^ F. At the end of that time 

 it had parted with its combined water, or at any rate with suffi- 

 cient to cause the colour to change from brown to bright red. 

 It still, however, retained organic matter, and on heating for a 

 few minutes in a tightly closed crucible, and at a temperature con- 



