276 Brush and Dana—the Spodumene of Branchville, Conn., 
plex pseudomorphs, in which they differ essentially from the 
Chesterfield specimens. 
II. RELATION IN METHOD OF OCCURRENCE BETWEEN THE VARIOUS MINERALS 
PRODUCED BY THE ALTERATION OF THE SPOD 
The individual characters of the several minerals produced 
from the change of the spodumene have already been given, 
and something has been said as to their mutual relations; it 
seems best, however, to add a few more general remarks as to 
their method of occurrence. 
Spodumene and £ Spodumene-—The way tn which these 
two minerals occur together will be better understood from 
fig. 5. As indicated in this case, the alteration product, # 
spodumene, forms a more or less thick crust about the original 
mineral, and also penetrates in bands which follow the direc- 
tions of the cleavage surfaces, and which are sometimes mere 
lines and again have considerable thickness. It is worthy of 
union is examined under the microscope. It is consequent 
necessary to conclude that while the alteration went on grad- 
ually there was chemically an abrupt change from the one 
substance to the other. As already remarked, the analysis 2 
of 8 spodumene was made of a portion, which, though apparently 
ure, immediately adjoined the cymatolite, and the result is 
identical with the others, where the idea of a regular gradation 
could not be suggested. Many of the large crystals of cyma- 
tolite, when examined Laretanly. show a trace of the other 
mineral, and we are forced to believe that at least for this 
locality it always preceded it. : 
