FEBRUARY 16, 1912] 
ress; and many instances have been made 
known to us by the observations of other 
workers. Therefore, the commonly ac- 
cepted conclusion that recession is the gen- 
eral rule among the Alaskan glaciers is fully 
warranted; yet the rule is by no means 
invariable. For example, Columbia Gla- 
cier began advancing in 1908, and Pro- 
fessor Martin found it still advancing in 
1910, while in the same year he observed 
commencement of advance of several gla- 
ciers of different sizes in Prince William 
Sound and Copper River valley. We 
know also of recent advance of other 
Alaskan glaciers, the total known to us to 
have advanced since 1899 being 43, nine 
of which are in Yakutat Bay; but some of 
these 43 advances are exceedingly slight; 
and 43 glaciers form but a minute propor- 
tion of the whole number of Alaskan gla- 
ciers. These facts demonstrate that it can 
not be assumed either that the recession is 
universal, or that it is not liable to inter- 
ruption. ‘Too little is known about Alas- 
kan glacier history and about Alaskan cli- 
mate and its variations to warrant any 
generalization with regard to the possible 
future of its glaciers; it is not even certain 
that the present state of general recession 
is anything more than an episode. 
Advance of Glaciers as a Result of Earth- 
quake Shaking 
Of all the recent glacier advances of 
which we have record in Alaska, by far the 
most interesting are those of Yakutat Bay. 
Following the vigorous earthquakes of Sep- 
tember, 1899, and, as I have elsewhere en- 
deavored to show,® as an indirect result 
13] have presented this theory in various pub- 
lications, and in these have given a full state- 
ment of the facts and a discussion of their bearing 
on the theory; so that, in view of the character 
of this address and its necessary briefness, only a 
very short and general statement is attempted. 
See especially Tarr, R. S., ‘‘Second Expedition 
SCIENCE 
251 
of them has come a series of forward move- 
ments and transformations of a very spec- 
tacular character, interrupting a period of 
general recession and affecting even stag- 
nant glaciers and piedmont bulbs. First 
there came a spasmodic advance of at least 
two small glaciers, and probably others 
that we failed to detect on our first expedi- 
tion in 1905; then, in the interval between 
September, 1905, and June, 1906, an ad- 
vance occurred in four larger glaciers; in 
1906 and 1907 the Hidden Glacier ad- 
vanced; in 1909 the still larger Lucia Gla- 
cier; and in 1909-10 the Nunatak Glacier 
advanced. The progressive appearance of 
the advance, correlated with the length of 
the glaciers, has been set forth in the fol- 
lowing table prepared by Professor Martin: 
Approximate 
Name of Date of Length of 
Glacier Advance of Glacier 
Galiano ........ After 1895 and 2 or 3 miles 
before 1905 
Unnamed Glacier 1901 3 or 4 miles 
Haenke ........ 1905-6 6 or 7 miles 
Atrevida ....... 1905-6 8 miles 
Variegated ..... 1905-6 10 miles 
Marvine ....... 1905-6 10 miles (ex- 
clusive of por- 
tion in Mala- 
spina piedmont 
area) 
Hidden ........ 1906 or 1907 16 or 17 miles 
Gucianeneeeeceic 1909 17 or 18 miles 
Nunatak: a. l 1910 20 miles 
The advance involved a profound break- 
ing of the glacier surface even where pre- 
to Yakutat Bay, Alaska,’’ Bull. Geog. Soc. Phila- 
delphia, Vol. 5, 1907, pp. 1-14; ‘‘Recent Advance 
of Glaciers in the Yakutat Bay Region, Alaska,’’ 
Bull. Geol. Soc. America, Vol. 18, 1907, pp. 257— 
286; ‘‘The Yakutat Bay Region, Alaska,’’ Pro- 
fessional Paper No. 64, U. S. Geol. Survey, 1909; 
‘The Theory of Advance of Glaciers in Response 
to Narthquake Shaking,’’ Zeitschrift fiir Gletsch- 
erkunde, Vol. 5, 1910, pp. 1-35; also Tarr, R. S., 
and Martin, Lawrence, ‘‘ Recent Changes of Level 
in the Yakutat Bay Region, Alaska,’’ Bull. Geol. 
Soc. America, Vol. 17, 1906, pp. 29-64; ‘‘The 
Yakutat Bay Earthquakes of September, 1899,’’ 
Professional Paper No. 69, U. S. Geol. Survey, 
1912 (in press). 
