The Pegmatyte Veins of Pala— Waring. 369 
tion, — facts according with the conditions revealed in new- 
ly opened pockets. Perhaps the best example of alteration 
is presented in the pockets at Rincon. Here corroded 
crystals of orthoclase (plate xxvi. fig. i) and corroded beryls 
(plate xxvi. fig. 2) occur together in a matrix of sticky red 
clay composed for the most part of iron-stained mica and 
kaolin. It seems clear that the microcline has first yielded 
to the meteoric waters and been reduced to kaolin and mica. 
The waters, made more alkaline by the liberated potash, 
have then attacked the beryls and partly dissolved them.. 
Muscovite often occurs as fine flakes on the larger beryls, 
seemingly as a product of alteration. The very interesting 
series of reactions that have taken place here well deserve 
further study. The relation of the amblygonite to lepido- 
lite, the decomposition of spodumene and the reactions be- 
tween the feldspars and beryl especially present reactions 
worthy of examination. Some attempt has been made to 
trace the rare elements when alteration takes place, but 
no secondary minerals of boron or beryllium, derived 
from tourmaline or beryl, are known to occur ; neither do 
ordinary tests show the presence of these elements in the 
surface waters. It seems probable however that they are 
carried off as soluble salts, but in quantities so small as 
easily to escape notice. The failure to find lithia in these 
waters might be expected, for the lepidolite is always fresh- 
and unaltered. 
