152 ‘RB. WILLIS—DRIFT PHENOMENA OF PUGET SOUND. 
great detail and with reference to all the formations related to it. It 
may then yield important data bearing on phases of the interglacial 
history. . 
ADMIRALTY GLACIAL EPOCH ° 
General statement.—Beneath the Puyallup stratified formations are un- 
stratified deposits characteristic of glacial conditions. They record a 
glacial advance which was probably quite as extensive as that of the 
Vashon epoch, but which can never be known in the same complete de- 
tail, as the till and its associated beds are deeply buried. The principal 
exposures of these glacial formations are to be seen in the bluffs along 
the shores of Admiralty inlet. The name Admiralty is therefore given 
to the epoch. 
Admirally till and clays.—This formation was first recognized by Russell 
during his reconnaissance, although referred to, from Everett to Tacoma. 
In his brief report he describes it as 
“A thick deposit of stiff, blue clay, usually in evenly stratified beds, but occa- 
sionally changing gradually to a well characterized till filled with subangular stone 
and gravel, together with occasional boulders, some of which are glaciated. This 
deposit is frequently exposed about the immediate shores of the Sound, and forms 
precipices from a few feet to fully one hundred feet high. 
““The upper surface of the lower till is irregular in many places and sometimes 
deeply eroded. For this reason it is not seen at some localities where it might be 
expected to occur, its place being taken by stratified sands and gravels.” 
Within the area which I have personally examined the Admiralty for- 
mations are rarely exposed. The observations may be noted as follows: 
At Tacoma stiff blue clay, minutely bedded, forms a vertical bluff 
above the steamer wharf. As the clay turns water and is overlain by 
the porous sands of the Tacoma delta, its upper surface is marked by a 
line ofsprings. In the southeastern part of the city, nearthe freight depot 
and 380 to 40 feet (10 to 12 meters) above sea, are sections of sandy clay 
containing large boulders. The deposit is unstratified. The absence of 
structure and the association of coarse and fine material identify it as a 
true till or ice-laid formation. Its characteristics are shown in plate 10. 
Along the western shore of Des Moines island the Admiralty till occurs 
occasionally near sealevel in places rising in bluffs 10 to 40 feet (3 to 12 
meters) high, and again passing out of sight below tide. -It is a stiff 
sandy clay with numerous rounded pebbles and angular stones. 
On the eastern side of the Duwamish valley near Kent a till, which is 
correlated as the Admiralty, occurs below the Vashon till separated by 
finely stratified sands. Ina gulch 3 miles (5 kilometers) southeast of 
Kent this lower till occurs as a nearly vertical scarp between the eleva- 
tions 120 and 175 feet (37 to 53 meters) above sea. It is a bluish gray, 
