Colton's map of Oregon & Washington Territory / issued by the Oregon State Board of Immigration ; prepared by G.W. & C.B. Colton & Co.G.W. & C.B. Colton & Co[1879?]"Entered according to act of Congress in the year 1879 by G.W. & C.B. Colton & Co. ...."Includes ill. of steamships along Oregon Steamship Co. and Alaska & Sitka Steamer routes.Prime meridians: Greenwich and Washington, D.C.Relief shown by hachures.Shows Oregon, Washington, and western Idaho.cartographic