i6 The Ottawa Naturalist. [April 



almost similar instances could be cited from many localities, 

 did time permit. 



If, however, we were to go on and relate many such cases, 

 there would be but little time for the matter proper of this paper, 

 and I will pass from the consideration of this subject by saying 

 that with many men who become infected with the mining fever> 

 so peculiar is their disposition, that in many cases the advice 

 of a competent mining or geological expert is very apt to be 

 disregarded, most people preferring probably to cure themselves 

 of the disease in their own peculiar way. 



With regard to the leading geological features of the 

 mineral bearing areas of the Ottawa District it may be said that 

 these are referable to two divisions of rocks, viz., the Palaeozoic 

 and thecrystalline. Concerningthe origin of the rocksof theformer 

 there is no great doubt. They arc sedimentary, and contain in 

 their mass the traces of organisms peculiar to the age in which 

 tliey were deposited, All these fossiliferous deposits have been 

 arranged in due order like the pages of a great book, by turning 

 which a clear and comprehensive history of the growth and 

 development of the earth's crusr, for this portion of its history, can 

 be obtained. 



When we come to the question of the underlying crystalline 

 rocks we have a different s'ory. Formerly these were regarded 

 by many as having originally the same origin as the newer rocks, 

 that is,the greater part were also held to be sedimentary deposits. 

 Recent studies, both in the field and in the laboratory, have 

 however led to a marked change of opinion in this respect, and 

 it is now very clearly established, that a very large proportion of 

 the crystalline rocks have been produced without the agency of 

 water in the ordinary sense, but are distinctly and directly igneous 

 in their character. In this way we have come to regard many 

 of the rock masses, with which our most important minerals are 

 associated, as intrusive through the sedimentary deposits, and 

 this peculiarity of intrusion has in many cases, had a very im- 

 portant bearing upon the development of the associated minerals. 



The principal rocks of the crystalline, series, which in 

 Canada have been, for the most part, long regarded as 



