And that the bed of the same river, and the islands and dry land within the same, so as aforesaid assigned and belonging to this state, lying southerly of the line last aforesaid across the said river, and northerly of a line from the extremity of the boundary of the counties of Bucks and Philadelphia, at the bank of the river Delaware, across the said river, by a south-east course, to the shore of the state of New Jersey, are annexed to and shall be deemed to be, and shall henceforth be, parts of the county of Bucks, and of the several adjoining townships and precincts of the same county, lying along the said river.