OCCURRENCE OF PRECIOUS STONES IN N.S.W. 273 
. these garnets cannot be pyrope. Taking the recognised classifica- 
tion of the garnet group, we find that pyrope is a subdivision 
where magnesia predominates in atomic proportions over the other 
protoxide bases ; or, that the ratio is at least Mg : : Ca: Fe + Mn 
=3:1:2, or that Mg equals the other protoxides, or the ratio 
isas 1 tol. In an analysis published by Dana, and stated to be 
of high merit, it is as 1 to 87. But if we take the analysis of 
the so-called _Pyrope given in the paper, we find that the ratio is. 
Mg : Ca + Fe + M = 3: 6:18 or a ratio of 1 to 2 as shown by 
the figures given. Taking the protoxides only, the oxygen ratio 
works out as follows :— ratio 
FeO = 10-04% contains oxygen = 2°23=1-911 
MnO = 3-76,, ‘ i », 0°85 = 0-729 | = 6°18 
CaO = 14-45 ,, », 4:13 =3'540 
9 - », 350=3°000 = 3 
On behalf of mineralogical science in New South Wales, I 
object to priority being given for pyrope to a garnet with a. 
composition so diverse from that required to form the species. 
If pyrope is announced, it should be for a garnet that by its per- 
centage composition, shows legitimate claim to the name. The 
garnets from the sandstone at Sydney, described by myself in 
the proceedings of this Society two years ago, contain more 
magnesia than those in this paper, yet by no stretch of imagina- 
tion can they be construed into pyrope. If we are to adhere to- 
the oxygen ratio for this class of silicates, we must take some 
notice of the recognised basis on which these species have been 
formed, and not attach names to minerals merely because they 
“pproach others in some constituents. It is evident therefore 
that on a scientific basis these garnets are not entitled to be con-. 
sidered ag pyropes. In the classification of the garnet group into- 
its several subdivisions, sufficient latitude i is given, by recognised 
authorites, for foreign constituents that exist more or less in all! 
garnets, but this limit cannot be recklessly ignored. 
Professor Davin wished to know the evidence on which the- 
Statement, made by the Rev. J. Milne Curran, was based that- 
R—Oct. 7, 1896, 
