It was in such circumstances that McClellan at last undertook to use the great army he had created, for the purpose it was meant to accomplish. Early in the spring, he transferred 120,000 men by water to Fortress Monroe, leaving seventy thousand at and near Washington, to hold that capital secure. Somewhat more than half of this force at Washington was to advance upon Richmond by way of Fredericksburg, and add forty thousand men to McClellan's great army when he should sit down before the Confederate capital. He, meanwhile, was to march up the peninsula formed by the York and James Rivers, supported by the navy on either side. Richmond was seemingly doomed, and everywhere at the North the expectation was that McClellan, with his overwhelming forces and his well-nigh perfect organisation, would make an end of the war before the first anniversary of the battle of Manassas. If McClellan had been half as capable in the field as he had proved himself to be in the work of organisation, this might easily have happened. But he was cautious to a positively paralysing degree. It was his habit of mind to overestimate his enemy's strength to his own undoing. Thus when he began his advance up the peninsula, with nearly sixty thousand men, to be almost immediately reinforced to one hundred thousand and more, he found a Confederate line stretched across the peninsula at Yorktown. It consisted of thirteen thousand men under Magruder, and with his enormous superiority of numbers, McClellan might have run over it in a day, while with his transports, protected by gunboats, he might easily have carried his army by it on either side, compelling its retreat or surrender. But in his excessive caution he assumed that the entire Confederate force was concentrated there, and his imagination doubled the strength of that force. He confidently believed that the Yorktown lines were defended by an army of eighty thousand or more, and instead of finding out the facts by an assault, he wasted nearly a month in scientifically besieging the little force of thirteen thousand men, with an army six or eight times as great, and a siege train of enormous strength. When at last he had pushed his siege parallels near enough for an assault, he found his enemy gone, and discovered that the great frowning cannon in their works were nothing more than wooden logs, painted black, and mounted like heavy guns. The North had not yet found a general capable of commanding the superb army it had created, or of making effective use of those enormously superior resources which from the beginning had been at its disposal. Grant had splendidly demonstrated his capacity at Shiloh, but Halleck had immediately superseded him, and completely thrown away the opportunity there presented. Grant was still denied any but volunteer rank, and for many weeks after Shiloh he was left, as he has himself recorded, with none but nominal command, and was not even consulted by his immeasurably inferior superior.