Wadsworth.] 
102 
[November 17, 
Now the statements are: 
K The writer has regarded it, as he has long since explained (this Jour- 
nal, xlix, 49, 1845), an insuperable objection to the theory of infiltration 
from above, that surface waters can get into amygdaloids by means of infil- 
tration downward only a short distance — in some not an inch ; and that, 
however deep, the result caused by the waters and the accompanying air is 
oxidation and the discoloration and destruction of the rock. ( The waters 
of hot springs might produce depositions in cavities or fissures that open 
upward ; but it appears to be physically impossible that such waters, what- 
ever they may hold in solution, should penetrate deeply through the mass of 
a cold trap or amygdaloid containing disseminated copper in grains, and 
take up and transport that copper into amygdaloidal cavities, fissures and 
joints. Surface waters sometimes descend for yards along the joints; but 
when so, the surfaces of the joints indicate it by their iron rust discolora- 
tion. ****). * * * * I believe that the most satisfactory theory of the 
origin of the ores and associated minerals is that which I have hitherto 
held, only slightly modified : that the copper came up with the igneous 
rock, and so also the moisture that made the steam cavities of the amygda- 
loid, though neither was derived, the one nor the other, from the deep- 
seated source of the eruption, but from sources encountered on the way 
up; that, while the rock was slowly cooling through the range of tempera- 
tures from that of fusion, over 2000° F., to 212° F. (when at last the vapors 
began to lose their chemical activity), and thence to 100° F. and below, 
the igneous material sooner or later received its vapor-made cavities in 
places where the pressure wfis little enough to permit it and the moisture 
was abundant enough to produce them, and the rocks also became jointed 
and fissured through the progressing contraction ; that other fissures may 
have been opened by new subterranean movements while the cooling was 
going forward, that is, before the era of eruptions for the region had 
passed, and gave passage for ascending vapors and whatever they, bore 
along; that the moisture which made the amygdaloidal cavities was the 
moisture which altered the pyroxene or other minerals of the rock to 
chlorite, and made the zeolites and quartz out of chiefly its feldspars, and 
that this kind of transformation of the igneous rock near all cavities or 
fissures into quartz and hydrous silicates kept going on as long as the rock 
was undergoing its refrigeration, different minerals resulting at different 
stages in the temperature ; and that the copper which came up with the 
igneous rock was, in the course of the cooling, carried by the aid of the 
vapors into fissures, and so formed veins, and into other cavities to help 
make amygdules at the same time that other minerals were making them, 
and so produced sometimes a cupriferous amygdaloid ; and that simulta- 
