Despite their desperate resistance and the untiring activity of the 1st Cav. Div. and 2nd Corps—units of which galloped from breach to breach to re-establish the liaison and retard the enemy onrush—General Robillot's group fell back towards Roye.
March 25.
The road to Amiens open to the enemy.
South of the Somme, the situation was still more critical. The remains of the British 18th and 19th Corps withdrew to the line Chaulnes-Frise, which they were, however, unable to hold.
Their retreat continued to the line Proyart-Rosières. No more reserves were expected for four days. Should the Germans succeed in crushing these exhausted units the road to Amiens would be open.
About six miles behind the Proyart-Rosières front, there was an old French line, partly filled in, on the Santerre Plateau, between the Somme (at Sailly-le-Sec) and the Luce (at Demuin).
A battalion of Canadian Engineers was ordered to restore it. However, there were no troops to hold it, and as its abandonment would have imperilled Amiens, Gen. Gough decided to muster an emergency detachment of engineers, miners, electricians, mechanics, staff personnel, pupils and instructors from the schools of the 3rd and 5th Armies, and American sappers, in all about 2,200 men. This detachment, under Maj.-Gen. Carey, was ordered to hold an eight-mile front and bar the road to Amiens.
North of the Somme, the Germans attacked from Ervillers to the river; the British left stood firm, whilst on the right, the hinge formed by Byng's Army, likewise resisted. Further south, the Germans captured Maricourt, and broke through the curtain of British troops, which lost contact with one another. The Ancre was crossed, and Byng's right, pivoting on Boyelles, fell back on the line Bucquoy, Albert, Bray-sur-Somme.
General Pétain issued a stirring appeal to the men:
The enemy is attacking in a supreme effort to separate us from the British, and open the road to Paris. At all cost, he must be held. Stick to the ground, stand firm, reinforcements are at hand. United, you will fling yourselves on the invader. Soldiers of the Marne, Yser and Verdun, the fate of France is in your hands.