4 
MUSEUM BULLETIN NO. 15. 
a glossy appearance approaching that of a newly fallen meteor- 
ite, but on close examination this was found to be due to polish- 
ing of an oxidized surface by contact with the materials making 
up the gravels. The general surface colour is dark brown to 
brownish-black and is due to the coating of oxidized material 
which encrusts the specimen. 
This iron has recently been sliced, polished, and etched by 
the Foote Mineral Company, Philadelphia, Pa., to whom the 
writer is indebted for permission to use the photographs of one 
of the etched plates. The slicing revealed the presence of a 
number of inclusions of troilite, most of which were quite round 
and of small dimensions — 1 to 5 millimetres in diameter; an- 
other irregularly formed one measured 24 millimetres in length 
by 12 in width. One of these nodules, measuring 3 millimetres 
in diameter, is shielded on one side by a thin covering of a white 
metallic substance identical in appearance with an inclusion noted 
in the Gay Gulch iron; on the side of the nodule opposite to this 
shield the iron is marked by a number of cooling cracks. An- 
other minute inclusion of this same white metallic substance is 
to be seen in another part of the plate near one edge; the iron 
surrounding this inclusion is likewise marked by a number of 
cooling cracks. The first of these inclusions is shown together 
with portions of the cooling cracks in Plate VII. The treatment 
of the polished slice failed to develop any etch figures properly 
so called. There was developed, however, a peculiar chatoyant 
effect which is to be seen by holding the plate at different angles 
to the line of vision. Thus when the plate is held in one position 
certain portions appear quite dark while the remaining portions 
appear bright, but if the plate be rotated through an angle 
of between 50 and 60 degrees, the eye of the observer being 
kept in the same position, the positions of these dark and 
light portions become reversed, that is to say, what was dark 
in the first position becomes light in the second position. This 
property which is illustrated in Plates VIII and IX is clearly 
due to a definite crystallographic arrangement, and is strongly 
suggestive of octahedral twinning. 
Under moderate powers of the microscope the etched plate is 
seen to vary in character in different portions. Near the inclusion 
