TWENTY-FOURTH ORDINARY EETING. 301 



form may have been imparted to them, either during or subsequent 

 to their formation. 



The structure I have attempted to describe is best seen where the 

 phosphate-producing rock is least disturbed and where the joint-fissures 

 are moderately small and close together, but the same arrangement 

 obtains among the larger deposits. The principal mass in a working 

 sometimes passes from a vertical joint to one in another set, or from 

 one of the latter to a horizontal joint, thus giving the mass the form 

 of the letter |_ as seen in plan in the first instance or in vertical sec- 

 tion in the second. An example of the first of these forms on a 

 laige scale is described by Mr. Torrance as occurring at Major Chap 

 leau's Mine on lot 17, range YI, of Portland, East — (Geol. Survey 

 Eeport of Progress, 1882-84, page 16 J.) 



Along the intersections of any two of the planes of the joints, an 

 more especially at the points where all three intersect one another, 

 the apatite is accumulated in the largest quantity. The angles of 

 adjacent blocks are frequently rounded ofi" and thus larger spaces are 

 found for the deposition of the mineral. Sometimes the apatite 

 follows only one set of vertical joints, when it appears as parallel 

 veins ; at others it is nearly confined to the horizontal ones, when it 

 forms a succession of " floors," and again it may follow both of the 

 vertical sets or even all three, in which cases it appears in a reticu- 

 lating form, which is of very common occurrence. 



If the above view of the nature of the majority of our phosphate 

 deposits in the pyroxenite be correct, we should naturally expect to 

 find the mineral most freely exposed where upward movements of 

 the apatite-bearing rocks bad occurred, and that the deposits of the 

 mineral between the blocks of the country-rock would be widest 

 above, and further, that in going downward they would become 

 pinched towatds the next leading horizontal joint below, where they 

 would open out again ; also that the siiccessive bunches of the mineral 

 would become smaller and smaller in descending. These conditions 

 appear to correspond with the experience of mining so far. 



The great numbers of small " shows " which are found on the sur- 

 face among the apatite-bearing rocks appear to aflford additional proof 

 of the correctness of the view i have put forth. Many of these have 

 been worked to a small extent on the surface by farmers and others, 

 but the great majority of them show a tendency to pinch out at a 

 limited depth, when they are usually abandoned. As many as 300 

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