 Complete the following phrase:  On 15 May 1916, Princess Margaret laid mines off the Belgian coast to reinforce the existing minefields. Princess Margaret and Paris laid mines near the Thornton Ridge on 24 May 1916, and on 4 August 1916, the British light cruiser stuck a mine off the Thornton Ridge, probably from this minefield. On 18 May 1916, as a response to the German 