1908-9.] ON THE ORIGIN OF THE CANADIAN APATITES. ; 505 
Comment is scarcely necessary, but when we remember that the 
organic remains of the oldest fossiliferous strata contain a very high 
percentage of phosphoric acid and fluorine we are forced to conclude 
that in proportion as these deposits of calcium phosphate approach in 
age to apatite, they approach pari passu to its chemical composition. 
32. Apatite is a crystallized fluophosphate of calcium of a normal 
composition of 
ey Ovo CaiOx) an Carky.. 
which, if reduced to a formula gives us 
Cang. Pe 3 O12 
In such a compound the percentage of fluorine is 3.77 and the ratio 
between it and phosphoric acid F505 = 0.0892. Most apatites however. 
contain a certain amount of chlorine. Thus the composition of three 
specimens from Jumilla, Spain (1) and the Tyrol (II & III) are as follows: 
I II III 
1225) HO lelceatatmiante heed te  MAt7 (Al 41.91 41.97 
IF ests dase ate systema: sRewerten ee ahs 3.54 3.58 3.63 
(i lie, Seed rtake see pea oR NEHTO Ney” Uy, 0.20 0.03 
CAO ios aatns ccs a a SE O'S 55-00 54.65 
INS; OAR Bele a ie ona a tr 0.18 0.48 
SIO Me ease cat eens roe Vein es,3 0.80 
100.67 100.87 IOI.56 
The amounts of fluorine called for in the above specimens to com- 
plete the standard formula would be: 
I II III 
3-72 3-74 27h 
a considerable excess of that actually found. If we calculate the mole- 
cular weights of fluorine in each case which correspond with the given 
amounts of chlorine we obtain: 
I II Ill 
0.25 One 0.02 
which, when added to the amounts actually given by analysis, makes 
I II III 
3-78 3-69 3-65 
a much closer approach to the calculated amounts. These results which 
