28 FIELD MUSEUM OF NATURAL HISTORY 
doubtless to erosion during its passage to the earth. Other 
large meteorites shown in these cases are those of Long Island 
and Brenham, Kansas, Canyon Diablo, Arizona, and Toluca, 
Mexico. Of these the Long Island meteorite is remarkable as 
the largest stone meteorite known. As exhibited it is in several 
hundred pieces all of which once formed a single mass, the 
weight of which was about 1,300 lbs. When the mass fell it 
struck a ledge and thus was broken into the pieces shown. The 
characteristic pittings of the surface of meteorites are well 
shown on this specimen. Of the Brenham, Kansas, meteorites, 
two large and two small individuals and ten sections are shown. 
One of the large individuals weighs 465 and the other 345 lbs. 
The total weight shown is about 1,000 lbs. The sections show 
the characteristic structure of meteorites of this class, viz., a 
sponge-like mass of iron, the pores of which are filled by the 
yellow magnesium silicate, chrysolite. The distribution of this 
silicate is irregular, some parts of the masses being wholly 
metal. 
Of the Canyon Diablo meteorite nine individuals and five 
sections are shown. The largest of the individuals weighs 
1,013 lbs., and is one of the largest ever obtained from the lo- 
cality. The next smaller individual shown, weighing 265 lbs., 
is remarkable for the perforation about one inch in diameter 
passing entirely through it. Of the sections, several are etched 
and show the characteristic figures of the meteorite. These 
figures are broad and irregular. The small projecting particles, 
about the size of a grain of wheat, are cohenite, a carbide of iron 
little attacked . by the acid used in etching and hence standing 
in relief. In addition are seen larger nodules of oval form which 
are sulphide of iron, often surrounded by graphite or cohenite. 
Of the Toluca meteorites sixteen individuals and seven sec- 
tions are shown. The largest individual weighs 90 lbs. An- 
other individual shows shaping for use as a hammer. Such use 
of these meteorites was frequent in early times. The etched 
sections show the typical figures of this meteorite, with laminae 
about 2 mm. in width and of a regular network pattern. 
In the wall cases are shown the smaller specimens of the col- 
lection, also casts of meteorites. The casts are placed in the bays, 
the meteorites on the shelves above. In the three cases first in 
order from the entrance from Hall 61, beginning at the left, are 
