234 PROCEEDINGS OF SECTION C. 
tourmaline, fluorspar, topaz, &c.; while in the apatite veins, 
both in the veins and wall-rock, scapolite, hornblende, 
enstatite and magnesia mica. 
8. In their chemical and mineralogical characters we 
meet with many remarkable analogies between the tin and 
apatite veins on the one side, and their mother rocks on the 
other side. Thus, in the granites of many localities, cas 
siterite and tourmaline, and also several other characteristic 
tin-vein minerals, have been proved to be primary con- 
stituents of the eruptive rock; and, in general, all the 
elements which are characteristic of tin veins, such as tin, 
silicon, fluorine, boron, phosphorous, lithium, beryllium, 
uranium, niobium, tantalum, molybdenum, tungsten, &c., 
also occur in the primary granites. Several of these 
elements are also especially characteristic of granite-pegma- 
tite veins, for example, minerals like tourmaline, topaz, 
beryl, elements like niobium, uranium, tantalum, molyb- 
denum, &c. Perhaps even more remarkable is the analogy 
between the veins and the mother rock of the apatite veins. 
Thus, we only need remember that both the apatite veins 
and also the gabbros are remarkable for their richness in 
phosphorous, titanic acid, and magnesium silicates, also in 
calcium and sodium silicates. While, on the other hand, 
potash silicates in both cases play a minor ré/e. The high iron 
content (in the titanic iron and specularite), as also the 
small proportion of nickel, should be noted. The primary 
differences in the chemical relations between the tin and 
the apatite veins may be thus summarised:—Tin, boron, 
potassium, lithium, beryllium, fluorine, and phosphorous 
(together with uranium, niobium, tantalum,. &c.) in the tin 
veins are replaced by phosphorous, titanium, iron, magne- 
sium, calcium, sodium, chlorine, &c., in the apatite veins. 
Titanium occurs in the gabbro and in the accompanying 
apatite veins, in the place of tin in the granite and the 
accompanying tin veins. Iron magnesium, calcium, and 
sodium are, for the most part, replaced by fluorine. The 
high phosphoric content of the gabbros and the apatite 
veins may be contrasted with the low proportion of phos- 
phoric acid in the granites and in the tin veins, while more 
boric acid occurs in the latter than in the former. 
In his general description of these apatite veins, Professor 
‘Vogt mentions the presence of iron and copper pyrites, small 
quantities of galena, and zincblende, and also gold and 
silver. With the exception of the two latter, these are 
included under the term sulphides in the above comparison. 
They are not specially dealt with, because they occur in 
about equal quantities in both kinds of veins. 
