436 REVIEWS 
only the rarest instances deposits sulphides, while these salts are the 
characteristic deposit of waters of deep circulation. Since the bulk of 
the ore deposits, neglecting certain clearly recognized but minor 
classes over which there is no dispute, are made up of sulphides or 
their alterative products, it was held that the ores must have been made 
by the deeper circulation, and that the waters making the deposits 
must have been “‘ascending.’’ In the earlier portion of the paper 
there are statements making clear the relations between the two circu- 
lations, and showing that one is but the counterpart of the other 
(pp. 27-28); there are later numerous statements which throw the 
matter into confusion (pp. 39, 56, etc.) While there is not such a 
clear statement as would be desirable, we are led to infer that the 
waters of the deep circulation are in some mysterious way cut off from 
and different from those of the shallow circulation, and that they are 
connected with acertain deep region, or barysphere, “ the peculiar home 
of the heavy metals.” The existence of this region is inferred from 
the usual calculations based upon the difference in density between the 
earth as a whole and the rocks of the surface of the earth. The very 
existence of a barysphere, in the sense of a central region of the earth 
heavier by reason of a greater abundance of the heavy materials, is 
to be questioned,’ however, on many grounds. 
In the discussion of PoSepny’s paper, which followed its presenta- 
tion, some of his criteria were discredited, and Rickard struck the key- 
note when he stated that neither ascending nor descending was the 
proper term to apply to the ore-depositing waters, but that circulating 
was the true descriptive term. This was characterized by Posepny as 
“a step backward.” The most trenchant and significant criticism, 
however, was that of Professor LeConte, who showed the great improba- 
bility, if not actual impossibility, of any surface waters penetrating to 
the depth of the assumed barysphere, and who then _pertinently 
inquired, If the waters which deposited the ores were not meteoric in 
origin, where did they come from? Were they constituent waters 
originally occluded in the primal inagma? ‘This is on its face highly 
improbable, particularly in view of the fact, so clearly recognized by 
Posepny, that any ore deposit necessarily indicates the passage of a 
considerable body of water through the space now occupied by the ore. 
At the close of the discussion, then, we are left with the conclusion 
that ore deposits, in general, are formed by the circulation of under- 
See particularly Arrhenius, as cited by VOGT, of. ci¢., p. 638. 
