Skagit county shall consist of the territory bounded as follows, to wit: Commencing at midchannel of Rosario Strait where the dividing line between townships thirty-six and thirty-seven intersects the same; thence east on said township line to the summit of the Cascade mountains; thence south along the summit of said mountain range to the eighth standard parallel; thence west along the parallel to the center of the channel or deepest channel of the nearest arm of Puget Sound and extending along said channel to the east entrance of Deception Pass; thence through said pass to the center of the channel of Rosario Strait; thence northerly along said channel to the place of beginning.