CANADIAN APATITE. 33 



metamorphic action (before described). A discussion of this subject 

 is of little practical benefit, but I would merely i)oint out, in ^this 

 connection, that this cannot be its primary origin. Coprolites, as we ' 

 know, are the fossil excrement of animals. Now animals not being- 

 able to create any element, but only to assimilate and form new com- 

 pounds, it is obvious that they obtained the phosphorus, which they 

 possess as calcic phosphate, from the vegetable kingdom ; the vege- 

 table kingdom in like manner draws upon the mineral kingdom for 

 its raw material. Hence in some form or other the phosphate ex- 

 isted before this Laurentian period, even granting that animal life 

 was so abundant as to produce such a large deposit — a theory very 

 untenable rom the general geology and palaeontology of the period. 

 It should be remembered that many other mineral phosphates occur 

 in nature besides apatite. In a large number of cases the apatite is 

 closely associated with pyroxene, and there is evidence to show that 

 it has been derived, to a large extent, from this sovirce. In small 

 but appreciable quantities, phosphate of calcium has been showfi to 

 be a constituent of many metamorphic and igneous rocks. 



Apatite occurs both crystalline and massive ; the latter variety, 

 however, may be said to be moi'e or less crystalline in structure. 



The crystals are usually found in a mati'ix of red limestone, and 

 though presenting a very beautiful appearance are of little or no 

 value, owing to the great difliculty in separating them from the 

 limestone. Occasionally, however, large cavities of loose crystals 

 are discovered, the matrix having become disintegrated and decom- 

 posed by atmospheric and other agencies. 



The crystals consist of six-sided prisms with complete pyramidal 

 terminations, though often possessing one pyramidal termination and 

 one basal plane. In size, they vary greatly, viz., from those of less 

 than half of an inch in length and coiTesponding thickness, weigh- 

 ing only a fraction of an ounce, to those of many hundredweights. 

 A section of a good-sized crystal from this district is at the School 

 of Science, Toronto. 



The usual colour of crystals is green. Some, however, approach 

 white, while others are of a pink, yellow, or violet tint, and others 

 nearly black. Apatite in the massive condition shows the same 

 vai'iability, and in a more marked degree, with respect to colour. 

 The colour appears to be purely accidental, and is due to various 

 3 



