The board of chosen freeholders of any county bordering upon the Atlantic ocean, may appropriate and pay out of the county treasury into the treasury of the United States to and for the credit of the secretary of war to be used and expended by him or under his direction, for the erection and construction of any works, sea walls, bulkheads, jetties and devices necessary and proper to preserve the coast of any municipality in the county against encroachment by the ocean which may cause or tend to cause an inlet or inlets therefrom into inland navigable waters, and to protect the inland waterways, navigable rivers, public roads, boulevards and public property in the county, a sum equal in amount to the sum expended or about to be expended forthwith by or on behalf of the United States in the construction of any such protective works on the coast of the municipality, of which expenditure or purposed expenditure, a notice signed by the secretary of war of the United States addressed to the governor shall be sufficient evidence. Such notice shall be sufficient authority for the board of chosen freeholders, the county auditor and county treasurer to pay such sum.

Such amount may be taken out of any unexpended balances of any appropriations or any cash on hand not otherwise appropriated, and if such balances and cash are insufficient for the purpose, so much thereof as may be necessary may be included and raised in the next tax levy of the county.

Not more than one such auxiliary appropriation, which in no case under this section shall exceed fifteen thousand dollars, shall be made by any county for such works in or on the borders of a single municipality.

Any appropriation under this section shall be paid into the treasury of the United States to and for the credit of the secretary of war only in conjunction with a like equal payment from the municipality to be protected thereby.