IOWA ACADEMY OP SCIENCE 
171 
The banded appearance of arctic glaciers is well known. Its main 
cause seems to be layers of fine dust and minute rock-fragments. Nord- 
enskioldc" in particular, calls attention to the banded appearance of cer- 
tain arctic snow-fields in which^the dark zones were found to be due to 
minute black grains, most of which were found to be due to minute black 
grains, many of which were metallic in character. Chamberlin,!' in pre- 
senting some fine photographic views of the fronts of Bryant, Krakokla 
and other Greenland glaciers, specially emphasizes the conspicuous 
banded appearance. While he incidentally states that the dark particles 
are ^ ' mainly terrestrial, ’ ’ he gives no data upon which he bases his conclu- 
sion ; and he leaves it to be inferred that he regards at least a part of the 
material as perhaps meteoric in character. The myriads of dust-wells 
which the same author^ describes in' the surface of the great Igloodaho- 
myne glacier seem to have like significance. 
The great abundance of chondres in the abysmal deposits which cover 
the floor of the ocean is especially noted by Murray and KenaiNT in the 
reports of the Challenger expedition. These masses are largely com- 
posed of basic minerals, closely related to the earthly substance known 
as bronzite ; and, with small doubt, appear to be of cosmic origin. 
Some conception of the reality and importance of the heavenly swarm 
which is constantly reaching us may be gained when it is remembered 
how frecpient and numerous are meteoric falls. In each 24 hours there 
are, according to Young" no less than from 15,000,000 to 20,000,000 of 
meteorites entering the earth’s atmosphere. 
The frequency of meteoric irons and meteoric stones in the 
arid regions of the globe, and especially on the high dry plateaus, 
is particularly significant in this connection. While such falls 
are probably not more common in those districts than elsewhere, 
the peculiar climatic conditions tend to give them prominence. 
The clear air, the cloudless skies, and the high altitudes contrast sharply 
with the thick atmosphere and prevailingly cloud-covered firmament of 
the sea coast of humid lands. In the high, dry regions, the frequency of 
meteoric manifestations immediately arouses the wonder of the sojourner 
from cloudy countries. The constant stream of light-paths across the 
heavens reminds one, every night in the year, of the November meteoric 
showers of other parts of the world. 
*Voyage of the Vega, p. 18. 
tJournal of Geology, Vol. Ill, p. 568, 1895. 
Ilbid., p. 215. 
^Narative Cruise H. M. S. Challenger, Vol. II, p. 809, 1885. 
-Astronomy, p. 472. 
