Early in the morning of March 23 it was known that the enemy had crossed the line of the Somme at Ham. The Thirtieth Division had retreated upon {160} this important little town, which had been thrown into a state of defence by General Stanley of the 89th Brigade, but his garrison was so utterly inadequate to cover the ground that his dispositions were useless, as the Germans could get round him on either side. He had with him in the first instance two entrenching battalions, the 21st and 23rd, two companies of gas engineers, the corps cyclists, and a mere handful of infantry. Late on March 22 he was joined, however, by his own three attenuated battalions of the King's, each of which had been heavily engaged in different parts of the battle. At the same time the 90th Brigade dropped back to the left of Ham and the 21st to the right. The division was bare on both flanks, however, and it was determined to continue the retreat. The bridges were blown up and such rolling stock as was possible was destroyed, but there were very many stores in the town which had to be abandoned to the enemy. It was a very great disaster, for it supplied him with much, and indeed served him as an advanced base, all ready-made for his operations in this part of the field. As to the loss of the river line, it has already been explained that in these higher reaches it is a very slight barrier. [Sidenote: March 23.] When the enemy had taken Ham he pushed along swiftly towards Esmery-Hallon on the heels of the retiring Thirtieth Division. The Thirty-sixth Division, which had been assisted in its retreat by the 61st Brigade of the Twentieth, had crossed the Somme to the east of Ham, and was now to the right of the Thirtieth (right and left being used all through these operations on the supposition that the unit is turning and facing the enemy). The Thirty-sixth {161} Division crossed the Somme Canal at St. Simon, closely pressed by the enemy, and the 121st Field Company Royal Engineers and other sapper units performed great work under heavy fire, destroying no less than twenty-seven bridges. After the passing of the river by the Germans there were constant rearguard actions, one of the most spirited of which was at Villeselve, where the 9th Irish Fusiliers and the Royal Dragoons fought together and drove in the German vanguard. The general situation of Maxse's Corps upon the forenoon of March 23 was that the Thirty-sixth Division was over the Somme and near Golancourt and Bronchy, that the Thirtieth Division was dropping back upon Esmery-Hallon, and that the Sixty-first Division, retreating in the direction of Nesle had crossed the Somme at Voyennes and Offoy, continuing its retreat to the Nesle Canal. Between the Thirtieth and Sixty-first Divisions were the 60th Brigade on the right and the 59th on the left, who were also covering the Nesle Canal, but were quite ready to counter-attack should an opening present itself.