Kawishiwin Agglomerate.— Winchell. 365 
surfaces. This is revealed by fractures across them after the calcite 
has weathered out, which is the case in many instances. While these 
tubes are generally simple, and approximately round in section they 
are not always so, but they flatten out for a short space and return 
again to the pipe-stem shape, and sometimes they branch, or coalesce, 
and so far as observed they branch like a plant upwardly, or out- 
wardly, 7. e. toward the exterior surfaces of the rounded masses. 
Calcite is also common in the green envelope which surrounds 
these masses, but it is arranged in flattened, thin, lenticular 
sheets conformable with the fibrous structure of the schist, and 
hence in general position it is perpendicular to the position of the 
tubes. Associated with it, in the green schist, is a noticeable 
amount of bright pyrite in fine cubes. 
In the interiors of the rounded masses also can be seen irregu- 
lar deposits of calcite. All this calcite is coarsely crystalline 
and firm, with hardness rather above the normal. 
The interest which attaches to this rock centers in these tubular 
passages that converge from the outer surfaces of the rounded 
masses, and penetrate the latter to the depth of an inch, more or 
less. There is no exception; they are all marked with the same 
structure. The rounded masses are undistinguishable as rocks, 
from the rock about Ely. It has been supposed that such accum- 
ulations were agglomeratic, 7. e., that the rounded masses were of 
the nature of bombs thrown from volcanic vents, falling in an ad- 
jacent or surrounding ocean. It has been supposed that the light 
green country rock, in the midst of which this structure appears, 
is the result of oceanie solution and levigation on volcanic eject- 
amenta. Such ash and cinder when brought into contact with 
hot, or tepid, or even with cold, oceanic waters would easily be 
reduced to a non-differentiated pulp, from which some of the alka- 
line ingredients, being more soluble, would be removed, leaving 
the residue somewhat more siliceous. Upon consolidation a rock 
something like the greenstone seen at Ely might result. 
On the other hand, as already stated, it is claimed by micro- 
scopists who have inspected such greenstones, that they are ‘‘al- 
tered eruptives,”’ and that dynamic metamorphism has been the 
process that has effected their reduction to this condition, 
It seems, however, that these peripheral tubes show that these 
rounded masses were suddenly immersed in an element which 
differed in temperature and pressure from that to which they had 
