BANDED CLAYS. 21 
“Bergs immediately in front of the glacier are prevailingly either white, blue, or black 
in color. The white bergs are derived from the ice walls above the sea; the blue ones, which 
are often a beautiful Antwerp blue, rise from below the water; the purely black icebergs, 
which are by no means uncommon, rise mainly from the base of the glacier, though a few 
fall from the débris-covered portions of the ice front. 
“Tn his description of Muir Glacier, Reid postulates conditions exactly the opposite of 
those which Russell infers; that is, instead of a projecting ice foot Reid assumes that there is 
a projecting ice cliff. Only a few icebergs from Muir Glacier are discolored with débris, and 
Reid suggests that the discolored bergs mentioned by Russell came from the débris-covered 
parts of the glacier. 
“My observations were in harmony with those of Russell. In several instances blue 
ice was seen to rise from beneath the water, though none was observed to rise as far away 
from the ice front as Russell states. The abundance of débris-charged icebergs near Hubbard 
Glacier is far too great to be explained by supplies from the very small and almost stagnant 
débris-covered margins, or from the limited areas of medial moraine. Moreover, the blue 
bergs are exceedingly abundant near the glacier, and too numerous to be accounted for by 
melting and overturning so soon after their discharge. Furthermore, the great amount of 
ice which falls from above water indicates a rapid recession of that part of the cliff, far more 
rapid than the rate at which melting would be expected to cause the submerged part of the 
ice to recede. 
“Three conditions favor the projection of a submerged ice foot, as follows: (1) The 
warmer water at the surface of the fiord, causing undercutting of the ice there; (2) the cre- 
vassed, weathered, and thereby weakened upper portion of the glacier; (3) the attack of 
waves, especially those generated by the iceberg falls. 'The combination of these conditions 
would tend to produce a projecting ice foot, and the facts observed indicate the presence of 
such a submerged foot in this region. 
“The normal condition of iceberg discharge from these glaciers may be best stated by 
giving a description of an actual instance of the calving of large icebergs which were seen to 
fall from the south side of the Nunatak Glacier ice cliff. First a small piece fell from the face; 
then a pinnacle at the ice front rose 50 to 100 feet, reaching well:above the surface of the 
glacier; it then slowly turned over into the fiord, sending a large fountain of water to a 
height of 75 or 100 feet. Immediately following this another ice mass, clear and blue, arose 
from beneath the water’s surface, throwing it into renewed and still greater commotion, 
which lasted fully five minutes as the berg rocked to and fro. A great series of ring waves 
spread out for nearly ten minutes, causing a heavy surf on the coast to a distance of at least 
13 miles from the glacier. Prior to this fall there was almost no floating ice in front of the 
glacier; five minutes after the discharge of the iceberg there was a ring of very muddy water 
in which floated several thousand icebergs of small size and six good-sized ones, all clean and 
free from drift. The ring of icebergs kept spreading until it reached both shores, advancing 
a half mile in each direction in about twenty minutes.* * * The larger bergs, one of which was 
more than 100 feet long, rose at least 30 feet above the water.” Tarr, 1909, p. 31, 32. 
What I would call the lower clay-pit has now been described. In Figure 1, 
I have continued this section upward with a section 100 feet to the north. It 
is not possible to connect the two sections with absolute accuracy but from a 
close study of the two deposits and by leveling, the fairly complete section of 
the clays at this locality is as represented in Figure 1. 
Commencing with the group of annual deposits numbered (23). This 
