Association of American Greologists and Naturalists. 317 
The information presented had been obtained from an examination 
of more than eighty persons, principally masters of vessels engaged in 
the whale and South Sea seal fisheries, in the merchant service and 
Labrador fisheries, all of whom had seen icebergs; also from authentic 
published accounts. He adverted to the intense interest with which all 
glacial agencies were regarded, to explain the various phenomena of 
drift, the transportation of earth and large fragments of rock in a 
southerly direction, the abrading and furrowing of the rocks in the 
same direction, the distortion and bending of strata of clay, the forma- 
tion of bowl-shaped cavities, and of the peculiar longitudinal ridges of 
bowlders and gravel which occur in the drift. 
To throw light upon these phenomena, he had collected information, 
1. As to the mode of formation of icebergs, their original position, 
and the manner in which they had been detached. 
2. The magnitude and form of. those floating at sea. 
3. The direction, rate, and nature of their movement, the limits of 
their transport, their grounding and dissolution. 
4. The positive and negative testimony as to the transportation of 
fragments of rock and earth. . 
In the first place, it was shown by accounts given of northern and 
southern glaciers, that islands of ice are fragments which have been 
detached from those glaciers—that the fixed icebergs or glaciers of the 
Arctic and Antarctic shores are governed by the same laws, and ex- 
hibit the same general phenomena as the glaciers of the Alps. Like 
the Alpine glaciers, the fixed icebergs of the north and south polar 
shores are formed by the yearly accumulation of snow. Blocks of 
rock and earth are found on their surface and in their interior, as they 
are found on the Alpine glaciers. Several of the fixed icebergs of the 
' Antarctic were particularly described. Instances were cited where 
these fixed icebergs or glaciers had been strewn with stones transport- 
ed from a distance, which stones had been afterwards covered by new 
deposits of snow and ice, where large rocks were found in the perpen- 
dicular face of the glacier overhanging the sea, and where they have 
been covered with piles of sand and volcanic scorie. It was shown 
from the peculiar structure of these icebergs, their fissures, Wc. that 
they must advance into the sea precisely as the glaciers of the Alps do 
along the valleys. Instances of the detachment of icebergs from the 
glaciers were cited, and the immense waves produced from their fall 
were described—these waves lifting up large vessels upon the shores, 
detaching other bergs and dashing them to pieces, and loosening from 
them imbedded fragments of rock. 
2. The enormous mechanical power which might be exerted by mov- 
ing icebergs, was inferred from their great magnitude. Many were 
