GLACIAL LAKES OF PUGET SOUND 451 



of the glacial features of Puget Sound has hardly gone far enough to 

 justify definite conclusions on this question as yet. A brief descrip- 

 tion of the records of the principal glacial lakes of the region, as far 

 as they have been studied, is given here, since such data alone can 

 substantiate the preceding hypotheses and answer the question raised. 



GLACIAL LAKES OF HOOD'S CANAL 



The form of this remarkable body of sea water is that of a great 

 hook, the main portion of which is 50 miles in length and about two 

 miles in its notably constant width. The broad valley of the 

 Skokomish River joins the southern tip of the Canal from the west 

 in much the same fashion that the arm which makes the hook form 

 joins from the east. The topographic disposition of the trough of 

 Hood's Canal and the two tributary valleys is perfectly adapted to 

 the production of a lake of glacial water in front of the ice during its 

 retreat. The inclosing drift bluffs at the head of the Canal are 

 about 350 feet high, and from this altitude a gravel plain slopes 

 gently south toward Shelton. Two or three channels across it are 

 known in part, and probably represent escape of water from the 

 earliest and highest ponding at the head of the Canal. This early 

 lake was held to the level of about 350 feet in the main trough and 

 up the two north-trending arms, while the ice retreated northward. 

 The enlarging water-body reached the head of the northeastern arm 

 before any important change of level occurred. Near Clifton a pass 

 was exposed to Case's Inlet southward, lower than the gravel plain 

 to Shelton, and, with exposure, it became the discharge-way of the 

 glacial lake of Hood's Canal. The very distinct channel here is 

 60 feet deep, the col in it lying at about 220 feet A.T. The operation 

 of the Clifton outlet determined a new lake level, and may thus 

 define the second stage of the glacial lake of Hood's Canal. Discharge 

 from both the first and second stages was into the larger lake held 

 back of the Chehalis-Sound divide. 



The bluffs of Hood's Canal, followed northward, continue every- 

 where sufficiently high to have held the glacial waters up to the 

 Clifton outlet for almost the entire length of the Canal. The ridge 

 and trough arrangement of the topography is interrupted in the 

 broadest part of the peninsula between Hood's Canal and Admiralty 



