304 
The American Geoloo-ist. 
November. 1904. 
be a sharp line between them. One would expect to find brack- 
ish waters clear to the surface, and that even if the heavy 
waters rising w^ere diluted by affluents, they would retain the 
same general character, whereas the surface waters and the 
deep waters are chemically entirely different. If there was a 
tendency for the waters to descend, however, the rocks 
might naturally draw in fresh water of entirely different 
character from the outcrop. 
Figure illustrating original cavities in cV rock of the copper bearing series 
such as may have been originally filled with chlorine gases, as at "A" \vedgecl 
in between feldspar belts and an octagonal augite grain. 
Van Hise might however suggest that the present distri- 
bution of waters is a recent phenomenon, the present circulation 
being indeed downward, but much later than the origin of the 
copper. 
Now if vapors escape they must be present in proportion to 
their vapor pressure in the lava and can hardly wholly escape 
but must be present more or less in the rock moisture of the 
acid interstices which I have so fully described for the in- 
trusive rocks. But even in an effusive as the rock (above fig- 
ure) we see that between the crystal of augite and that of feld- 
spar, each having its own shape, is an angular space wdiich 
must have been originally a pore filled only with gas probably. 
