HIO The American Geologist. May, i897 
Between South Seattle aiul Chuckanut baj^ (Bellingham 
bay) no survivals of rock at the surface occur, so far as 1 am 
aware, on the eastern border of the sound. A boring, 500 
feet in depth at the city boundary, (Bay View Brewing Co.) 
a few hundred feet north of Fossil blulf, is wholly in drift. 
Beyond the Restoration Point uplift of which Fossil blutf is 
a survival, no solid basal formation has been discovered to 
the south, even in a deep boring (400 feet) at Delhi, short. 
that is, of the solid border of the sound basin as traced in 
the foot hills of Mt. Ranier and in the Chehalis watershed. 
A few isolated basaltic outcrops above the drift mantle occur, 
as I am informed by Mr. Whitworth, in Thurston county, 
south of Olympia near Tumwater and Beaver, and still 
higher up the Des Chutes river. The accompanying profiles 
deduced from contours of government charts and maps, 
already cited, are intended to indicate the immense vertical 
development of drift both above and below tide, and to con- 
vey some idea of the degree of glacial erosion incidental to 
the evolution of the present tideways. 
Two important vertical sections of the drift mantle have 
been obtained and graphically plotted: — namel}?^, of the 
"South Sewer Shaft" at Seattle, one mile north of Fossil 
bluff, furnished by Mr. Thompson, city engineer; the otlier, 
also from shafts, sunk on -'school section" No. 16, Tacoma, 
in the course of an investigation conducted by myself for 
the State of Washington, of contested "'mineral applica- 
tions." The former comprises a section of 270 feet above 
mean high tide, the latter 370. Neighboring borings in both 
parts of the sound basin, previous!}^ mentioned, serve to add 
to these closely observed sections gross measurements of fur- 
ther depths of 500 and 400 feet respectively. Generally 
similar sections are constructively obtained at intervals 
from land reliefs and marine soundings. The divide between 
the sound and lake Washington rises to a bight of 450 feet. 
Thicknesses of drift up to 325 feet are exposed in many bluffs 
bared by recent landslides, as at Magnolia blutf, Duwamish 
head, Alki point, etc. Soundings off some of these precipi- 
tous shores give depths of upwards of 900 feet. In lake 
Washington and Hood's canal (inlet) soundings are reported 
from 600 to 700 feet. The minimum or measurable thickness 
