The Phosphates of America. 35 



A cooking and boarding house to accommodate, say, 250 men. 

 A sleeping-house to accommodate, say, 250 men. 

 A large warehouse for stores of all kinds. 

 Offices and dwelling for a local superintendent. 



It has already been explained that the form in which the phos- 

 phate occurs in the Canadian mines is that of a hexagonal crystal- 

 line mass of fluor-apatite. Sometimes it is extremely compact ; 

 at others it is coarse and granular. It has a hardness of 5 and a 

 mean specific gravity of 3.20, and is generally so friable as to fall 

 to pieces if struck with the pick. It varies in color from green to 

 blue, red, brown or yellow, according to the greater or lesser pro- 

 portions of impurities with which it is contaminated. 



A series of our analyses made from average samples taken from 

 many of the largest working mines may be regarded as very fairly 

 representative of the average chemical composition of the ma- 

 terial. 



COMPOSITION OF COMMERCIAL, SAMPLES OF CANADIAN APATITE. 



1st Qual. 2d Qual. 3d Qual. 



Phosphate of lime 88.20 78.65 66.22 



Carbonate of lime 4.13 8.05 9.20 



Fluoride of lime 3.10 3.04 2.97 



Alumina and iron oxides 0.70 1.03 1.37 



Magnesia 0.20 0.31 0.47 



Insoluble siliceous matter. . 3.67 8.92 19.77 



100.00 100.00 100.00 



What is the origin of these remarkable phosphates is a question 

 that has been, and still continues to be, the cause of much contro- 

 versy. 



Sir William Dawson, in a paper read before the Natural Histor- 

 ical Society, Montreal, 1878, " On the Phosphates of the Laurentian 

 and Cambrian of Canada," discusses the probability of animal origin, 

 and holds that there are certain considerations which point in this 

 direction. Among these are the presence of the iron ores, the 

 graphite, and of Eozoon Canadense, which he, with others, holds to 

 represent the earliest known forms of life. He further says that 

 the possibility of the animal origin of this phosphate is strengthened 

 by the presence of phosphatic matter in the crusts and skeletons of 

 fossils of primordial age, " giving a presumption that in the still 

 earlier Laurentian a similar preference for phosphatic matter may 

 have existed and perhaps may have extended to still lower forms, 

 of life." 



