AMERICAN JOURNAL OF SCIENCE. 
[THIRD SERIES.] 
- Art. L—On the Genesis of Metalliferous Veins; by JOSEPH 
[Read before the National Academy of Science, April 17, 1883.] 
THE phenomena of metalliferous deposit by solfataric action 
at Sulphur Bank and Steamboat Springs have tended strongly 
to confirm what I had previously believed to be the most prob- 
able theory of vein-formation, and at the same time to give it 
more clearness and definiteness. _This paper, therefore, may 
be regarded as a continuation and development of the thoughts _ 
started in the previous ones. 
The structure, the mode of occurrence and the contents of 
metalliferous veins leave no longer any room for doubt that 
they have been formed by deposit from Solutions. If any 
doubt still lingered on this subject, they are now dissipated by 
the phenomena of deposit still in progress at Sulphur Bank and 
at Steamboat Springs. Among metallic ores cinnabar has long 
been considered a possible exception to this mode of deposit. 
The extreme volatility of this sulphide, the extreme irregularity 
of its veins, and its frequent occurrence in the immediate 
vicinity of comparatively recent volcanic action, have suggested 
that it may have been deposited in irregular fissures, cracks, 
cavities, etc., by condensation of its vapors, sublimed by vol- 
canic heat beneath. But the phenomena of Sulphur Bank and 
Steamboat Springs ought to settle this question forever. Cin- 
* This Journal, vol. xxiv, pp. 23, 1882, and xxv, 424, 1883. 
Am. Jour. So XXVI, No. 151.—Jury, 1883, 
