Skamania county shall consist of the territory bounded as follows, to wit: Commencing on the Columbia river at a point where range line four east strikes said river; thence north to the north boundary of township ten north; thence east to a point due north of the mouth of White Salmon; thence south to the township line dividing townships six and seven; thence west to the northwest corner of Klickitat county; thence south along the west boundary of said county to the Columbia river; thence along the midchannel of said river to the place of beginning.