VARIATIONS OF GLACIERS 425 
Prince William Sound.—Columbia Glacier, which advanced more than 
1,700 feet between 1908 and rg1o, has continued a slow forward movement, 
apparently due to climatic causes. The western margin advanced a little less 
than 100 feet from September 5, 1910, to June 21, r911. The Valdez Glacier 
continued to retreat from 1910 to 1911, the amount of recession from June, 
1909, to June, 1911, being reported by the late L.S. Camicia, of Valdez, as 36 feet. 
Kenai Peninsula.—Spencer Glacier, close to the Alaska Northern Railway, 
retreated only 36 feet between January 8, 1906, and June 26, 1911. Glacier 
streams from this ice tongue have deposited outwash gravels so that twenty 
trestles in a distance of 13 miles along the railway were filled and had to be 
abandoned. An elaborate and successful attempt to divert the glacial streams 
was carried out while the National Geographic Society party was at Spencer 
Glacier in June, t911. Asa result of the work of man in blasting a channel in 
the ice and producing two new subglacial stream courses, this glacier will 
probably retreat more rapidly in the next few years. Bartlett Glacier near the 
same railway is inactive and retreating. 
Yakutat Bay—A Boundary Survey party under N. J. Ogilvie visited 
Yakutat Bay in ro1z and took photographs from a number of sites occupied 
by Tarr and Martin in previous years. These photographs, furnished through 
the courtesy of Boundary Commissioner W. F. King, show the following: 
Nunatak Glacier, which retreated 23 miles between 1890 and 1909 and advanced 
1,000 feet the following year, made a further slight advance by the summer of 
tgt1. The front of Hubbard Glacier had almost the same position in 1910 and 
1911. The northern margin of Turner Glacier retreated slightly. The 
crevasses in Variegated Glacier, which was impassable in 1906, had so far 
healed by melting that in 1911 the Boundary Survey party traveled up the 
glacier toits head. Lucia Glacier, which was impassable in 1909, was traversed 
by the same party in 1911; so was Marvine Glacier, which was impassable 
in 1906. 
Glacier Bay.—Muir Glacier retreated about 2,000 feet between 1907 and 
August 30, 1911. The thinning of the glacier by ablation and flow is an even 
more impressive feature than the retreat of the tidal ice front. It was possible, 
for example, in 1911, to walk upon a beach where, in 1907, there was an ice 
cliff, and where, in 1892, the ice was 1,200 feet thick. Tree stumps 12 to 18 
inches in diameter, uncovered by the melting of the ice, show that the maximum 
advance of the eighteenth century was preceded by a minimum when Muir 
Glacier was even more emaciated than in ro1t. 
Other ice tongues in Glacier Bay which have continued receding are the 
following: Carroll Glacier had retreated so far that the eastern part of it did 
not touch the sea at low tide in ro1r. A great delta had been built forward 
from nearly the middle of the ice cliff. Ablation had also removed the western 
distributary of Cushing Glacier, which previously spilled over to Carroll 
Glacier. Grand Pacific Glacier is retreating less rapidly than it did between 
1899 and 1907, possibly because it is about to cease to be tidal. Johns Hopkins 
