816 The American Geologist. May, i8»7 
resultant of later oscillations having been to maintain the Pa- 
get catchment at a lower level than the strait of Fuca. This 
is still indicated by soundings. It is. true that material ero- 
ded from the upper portion of the drift mass in the Puget ba- 
sin by river action, and from the shores of the sound by action 
of the waves, has naturally found its way to the outer channel, 
there however partially to lodge under the retarding and pre- 
cipitating action of the strongest of ocean tides, not without 
marked effect on present soundings. Unequal depression in 
the way indicated may be regarded as sufficient in itself to 
afford explanation of the original confinement of sub-glacial 
drift within the Puget catchment independent of other causes 
as above suggested. Strong tides having taken possession of 
the sound, so again at the present day suspended material 
sluiced in by glacial and other powerful torrents is locally 
precipitated near their discharge. Even in seasons of violent 
and abrasive floods like those witnessed by the writer in the 
month of June, 1894, clear water remains a characteristic of 
the sound except off mouths of rivers. Circumstances of both 
kinds here referred to combine to promote silting up of the 
sound, and the formation of tide flats and deltas. 
Whether the original configuration of the basal structure of 
the sound basin was primarily or in a secondary way essenti- 
ally due to orogenic depression, or, on the other hand, to pri- 
mary glacial excoriation and deformation, there can be no 
question but the deep tideways of that basin are substantially 
due to post-glacial fluvial dissection of the drift filling by ex- 
isting rivers, as first pointed out by Dr. Newberr3^* 
Without differentiation from the fiorded type of rock-bound 
coast between the 49th and 50th parallels northwestward to 
Bering strait, the inlet of Puget sound regarded as a whole has 
recently been erroneously instanced by Shaler "as one of the 
greatest and most characteristic fields of fiord topography on 
the coast of North America." Except perhaps in point of 
resultant partial submergence, the physiography of that 
basin and border, as shown in the present paper, presents 
the widest difference from that of a fiorded or ice-carved 
coast.j- 
*An. N. Y. Acad. Sci., Ill, 1884, 265; Dawson, op. cit., (1890) 51. 
tThirteenth Ann. Rep. U. S. Geol. Survey, 1893, II, 203. 
