In the following paper I propose to present some facts of topography and of Pleistocene geology bearing upon the origin of the peculiar physiography of the Puget Sound basin. The observations were made during the summer of 1896 in the southeastern portion of the Sound basin, in the course of a careful survey of the Tacoma quadrangle and the adjacent districts. I was assisted by Mr George Otis Smith, of the United States Geological Survey, and was so fortunate as to be associated during the inception of the work with Professor I. C. Russell, who had spent the three weeks preceding in a reconnoissance of the shores of Admiralty inlet. The observations would have been far less complete and their interpretation less definite but for the aid and helpful discussion given me by these geologists.
The Cascade range and the Olympic range are mountain . . .