290 FieLD CoLuMBIAN MusEuM-—GEoLoecy, VoL. I. 
trusion of the more resistant grains. In many places, especiallyin the | 
vicinity of the pits, minute thread-lhke markings appear over the sur- 
face, sometimes in parallel and concentric series, but more commonly 
in arborescent forms which are often quite elaborate. Theseseries or 
systems of markings do not appear to run in any common direc- 
tion, but are differently oriented wherever found. I have noted no 
system more than one inch (2.5 cm.) in length, but several of about 
this extent. They resemble closely the lines of flow such as have 
been noted on the crust of the Stannern and other meteorites, and 
doubtless are of this nature, being formed by a minute portion of the 
substance of the meteorite becoming momentarily fused and flowing 
in a diversified path until cooled. Their course in some cases seems 
to mark the swirling of the same air currents which formed the pits. 
More extensive and larger ridges are to be observed over some por- 
tions of the crust. Three nearly parallel appear on the portion of the 
Rickseite just mentioned. Each is continuous for a length of from 3 
to 5 inches. These do not appear to be of the nature of the lines of 
flow above mentioned, but more nearly resemble the veins which stand 
out on some meteorites and probably mark a line of more highly re- 
sistant constituents. Sections cut at right angles to the crust and 
examined with the microscope exhibit little if any alteration on the 
crust surface. The mineral outlines seem to be continued sharply up 
to the edge, and except for a certain smoothness of contour a crust 
surface could not be distinguished microscopically from the surface of 
an interior portion. Occasionally a metallic grain protrudes from the 
general outline, but so far as the contour as a whole is concerned it 
appears to be the result of erosion rather than of fusion. 
The weathering which the mass has undergone since its advent 
upon the earth has affected it considerably. Even the larger frag- 
ments when broken open will be found to be deeply invaded by rust 
which has penetrated along cracks in every direction. Doubtless 
the great number of small fragments into which the stone was found 
to be broken when first discovered was due to this process of sepa- 
ration through weathering rather than to shattering caused by the blow 
of the mass upon the earth. The weathering has affected chiefly the 
metallic constituents of the stone, causing their oxidation, and 
this rust has penetrated and stained the meteorite deeply. The color 
of the weathered surfaces has thus been changed from the dark green 
of the unaltered rock to various shades of brown, a characteristic 
color being a light yellowish brown, almost white, spotted with dark 
or rust brown. | 
The depth to which this discoloration has extended, except where 
