Apatite Bearing Rocks. 217 



we are forced to conclude, that, like the great 

 masses of syenite and the numerous intrusions of dole- 

 rite, it is also of igneous origin. That it is clearly 

 intrusive in its character is evidenced by its occur- 

 rence in dyke-like masses and bands which sometimes 

 cut directly across the regular stratification of the banded 

 gneiss and limestone, and at others traverse these along the 

 bedding planes for some distance and then abruptly change 

 their course after the manner of other instrusions. In some 

 places a gneissic structure is perceived in the pyroxene, 

 but this, as in the case of the syenites, is doubtless a foliation 

 due to great pressure. The pyroxene dykes are of very 

 varying proportions, sometimes extending for long distances 

 as narrow belts of from one to fifty or more feet in thick- 

 ness, at other times presenting the form of great hills, where 

 they are mixed with sy en itic and dioritic rocks. The apatite 

 bearing dykes are frequently cut by later dykes of syenite, 

 diorite, feldspar or trap, beautiful examples of this interlacing 

 being furnished at many of the openings throughout the 

 mining districts on the Lievre and Clatineau rivers. 



Various opinions have also been expressed as to the form 

 in which the apatite deposits occur. By some they are 

 stated to be in beds, others assert that they present rather 

 the features peculiar to vein structure, while yet others 

 maintain that they partake of the nature of both beds and 

 veins. By far the greater part of these opinions is based 

 upon the assumption that the containing rocks are sedi- 

 mentary gneiss and limestone, the intrusive character of the 

 pyroxene being for the most part ignored. Thus Dr. Har- 

 rington in his very exhaustive report on the subject which 

 is found in the report of the Geological Survey for 1877-78 

 thinks that the views of the Norwegian geologists as to the 

 eruptive origin of apatite deposits, cannot apply to those 

 found in Canada, and supports rather the view put forth by 

 Sir Wm. Dawson that the mineral has been produced prob- 

 ably through organic agencies. In its present condition he 

 thinks that while confined almost entirely to pyroxenic 

 rocks, the structure of the deposits partakes more of the 



16 



