220 The American Geologist. April, 1892 
They are fragments of botryoidal or reniform masses of ore, and 
thus are of secondary origin. Starting away from the nuclei the 
ore has very much the form of fangs of double teeth—blunt, 
irregular, conical aggregations of fibres, now without any filling 
of any material between them, though when 71 s/t may have had 
red powdery ore or clay among them. Concentric structure is 
exhibited in one of the fragments. 
Now what is most peculiar in these samples is that they have holes 
through or running in them at different distances from the nuclei 
and from one another. Three inches is about the distance of the 
nearest hole seen from a center of growth, and those best pre- 
served are clearly shown in the plate. 
The points or chief characteristics to be noted appear to the 
writer to be: 
a. The shape or form of these holes or little tunnels. 
». The fact that they run roughly parallel to one another or at 
right angles to the fibres of ore, namely: nearly square across or 
through the specimens. 
c. The peculiar curvature of the grain of the ore surrounding 
these apertures, particularly clearly brought out in the case of the 
left hand or perfect hole seen in plate. 
d, That, beyond or to the right hand side (as viewed in photo) 
of these pear-shaped tunnels there exists a straight, smooth kind 
of ‘bedding plane” running forward to the next hole (where the 
fibre is bent round), or right to surface or exterior of specimen, 
as shown between A and B (lower side of view). 
ce, The apparent fact that had the formation of the ore contin- 
ued beyond B CC, the outermost hole—really a groove or 
channel now, because open on one side—would have been closed 
over in like manner to that seen about three inches to rear of it. 
[Of course it will be seen that the lower of the three <‘‘holes” is 
only half there, the corresponding half being broken away with 
the rest of the mass. | 
J. All the holes have the same cross section in form and meas- 
ure, just about the same diameter—a little over | inch the short- 
est way. Under a pocket lens the surface of parts of these hoijes 
(their walls) is seen to be mammillated, and throughout they are 
coated with a soft skin or film of red iron oxide. 
The outside surface of the specimen, 7. ¢. between B and C, the 
edge of which is here shown, is oddly polished, though not artificially, . 
I think. This edge or surface represents the limit of growth of 
