The moneys held by the State Treasurer pursuant to the Act of Congress cited in paragraph number 4a of Section 1 of this Act shall be allocated and accredited to each county in which lands acquired by the United States for flood control, navigation and allied purposes have been leased by the United States in the proportion that the revenue received by the United States as rental in each county bears to the total revenue received by the United States as rental in all the counties in Illinois as the same is determined by the Secretary of the Treasury and certified by him to the State Treasurer, except that when such leased lands are situated in more than one county the distributive share to the counties in which such lands are located shall be proportional to the area of such leased lands in the counties affected. The amount so accredited to each county shall be paid by the State Treasurer to the county treasurer thereof and such amount shall be appropriated and used as the county board may direct.