Such, in brief, was the experience of the three divisions which held the line of the Eighteenth Corps on March 21. The Twentieth Division in {104} reserve was not employed during the day, nor were its services needed, for Maxse's Corps, though attacked by eight German divisions, was able to hold its ground, thanks largely to the splendid resistance of the shock-absorbing battalions in the front line. Up to 4 P.M. of March 22 the enemy had made no permanent advance into the battle zone, but at that hour both flanks of the Corps had been turned at Maissemy in the north and at Essigny in the south, and the alternative was retirement or absolute isolation and destruction. It may then briefly be said that, thanks to the resolute resistance of the battalions in the forward zone, and to the solidity of those in the battle zone, the Eighteenth Corps was able to maintain its ground until it was ordered to leave it, and that save for some indentation of its front, especially at Contescourt, its main positions remained inviolate. [Sidenote: Third Corps. March 21.] Upon the right of the Eighteenth Corps lay the Third Corps, which covered the enormous front of 30,000 yards. Of the nine brigades in the corps, eight were in the line and only one in reserve, so that between the tenuity of the line and its want of support it was an extremely tempting mark for the German assault, especially as by ignoring the two brigades south of the Oise they could concentrate their whole force upon the six brigades in line in the north. It is true that the wide marshes of the Oise offered an impediment which covered part of the British line, but as already remarked, the waters were exceedingly low for the time of year, and the Germans very cleverly overcame whatever obstacle was left. The three divisions which formed Butler's Third Corps were the Fourteenth Light Division (Cowper), which extended as far south as Moy, the Eighteenth {105} Division (Lee) covering the ground between Moy and Travecy, and finally the Fifty-eighth Division (Cator) extending to Barisis, five or six miles south of the Oise. As usual, we will take them from the north, confining the narrative to the point at which the fighting in the front line came to an end.