the German defences and cavalry now continued the advance, one brigade in the Australian sector and two cavalry divisions in the Canadian sector. Aircraft fire by the new RAF and armoured car fire kept the retreating Germans from rallying. The Canadian and Australian forces in the centre advanced quickly, pushing the line forward from its starting point by 11:00 am. The speed of their advance was such that a party of German officers and some divisional staff were captured while eating breakfast. A gap long was punched in the German line south of the Somme by the end of the day. There was less success north of the river, where the British III Corps had only a single tank battalion in support, the terrain was rougher and the German incursion of 6 August had disrupted some of the preparations. The corps gained its first objectives but was held up short of the Chipilly spur, "a bare seventy-five-foot-high ridge" in an oxbow bend of the Somme near the village of Chipilly. The British Fourth Army took 13,000 prisoners, and the French captured a further 3,000. Total German losses were estimated to be 30,000 on 8 August. The British, Australian and Canadian infantry of the Fourth Army sustained about 8,000 casualties, with further losses by tank and air personnel, and French forces. German Army Chief of Staff Paul von Hindenburg noted the Allies' use of surprise and that Allied destruction of German lines of communication had hampered potential German counter-attacks by isolating command positions. The German General Erich Ludendorff described the first day of Amiens as the "Schwarzer Tag des deutschen Heeres" (the "black day of the German Army"), not because of the ground lost to the advancing Allies, but because the morale of the German troops had sunk to the point where large numbers of troops began to capitulate. He recounted instances of retreating troops shouting "You're prolonging the war!" at officers who tried to rally them, and "Blackleg!" at reserves moving up. Five German divisions had effectively been engulfed. Allied forces had pushed, on average, into enemy territory by the end of the day. The Canadians gained , Australians , the French , and the British . Second phase The advance continued on 9 August, though without the spectacular results of the first day. The battle was widened on the north and the south of the initial attack, with the