THE 
AMERICAN GEOLOGIST. 
Vol. XXXIV. OCTOBER, 1904. No. 4. 
GLACIAL AND MODIFIED DRIFT IN AND NEAR 
SEATTLE, TACOMA, AND OLYMPIA. 
By Warren Upham, St. Paul, Minn. 
PLATE XIII. 
These three cities in the state of Washing-ton. the first and 
second situated on the eastern shore of the southern part of 
Puget sound, and the third at the end of the most southern arm 
of the sound, are respectivly its foremost and second commer- 
cial ports, and the state capital. Last year I spent several days 
in their vicinity, examining the drift deposits of the region, 
coming to it by the Northern Pacific railway, and extending 
my journey across this drift area and a wide driftless tract on 
its southwest side, to the ocean shore west of Gray's harbor. 
Although my observations are necessarily very incomplete, 
as noted in this paper, it is hoped that they may serve some 
useful purpose as a slight contribution to the description and 
history of the very interesting glacial and modified drift for- 
mations of the Puget sound lobe of the ice-sheet.* 
The most notable feature of these formations seems to me 
to be the very large proportion of the modified drift, or stratifi- 
ed gravel, sand, and fine silt, deposited by streams discharged 
from the ice-sheet, apparently during the time of its final melt- 
ing and departure at the end of the Glacial period. In the 
greater part of New England and in Minnesota and North 
• Previous descriptions of these drift deposits, with discussions of their 
origin and stages of the Glacial period, have been given by Bailby Willis, in 
a paper entitled "Drilt Phenomena of PuRet Sound," Bulletin, G. S. A., vol. ix, 
1898, pp. 111-162, with five plates, containing many details of his observa- 
tions, and quoting from a manuscript report of a reconnoi-^sance by Pruf. I. C. 
RussRLL. A large part of the same studies is also presented bv Bailey Willis 
and George Otis Smith in the Tacoma Folio, No. 54, 1899^ of the Geologic 
Atlas of the United States. 
