Issued, May 1888, F.M. Thorn, Superintendent. Verified: B.A. Colonna, Assistant in charge of Office ; [Triangulation, Topography, and Hydrography] by C. Rockwell, Assistant ; Astronomical observations by G. Davidson, Assistant ; Magnetic Observations by G. Davidson, J.S. Lawson, E. Smith, and W.H. Dall, Assistants ; Verification of Hydrography by Lieut. Comdr. W.H. Brownson, U.S.N. Inspector of Hydrography ; The reduced drawing of Topography by H. Lindenkohl ; ...of Hydrography by A. Lindenkohl ; Topography and Sand [engraving] by H.C. Evans. General Lettering by A. Petersen and F. Courtenay. Title and Notes by H.M. Knight. Coordinates approximate (Greenwich meridian) Depths shown by soundings and gradient shading (in low water areas); relief by contours and spot heights Variation compasses Bar scales in statute miles, nautical miles, kilometers Buoy legend, explanatory notes, latitude and longitude of Portland (Astronomical station Balch), River Lights table Shows waterways, vegetation, islands, railroads, various buildings, topography, divisions of land, Portland city plan, "Oregon Railway & Nav. Co Shops & Grounds" "No. 641d," "Plate no. 2007," "Electrotype Copy No. 1..."