two divisions of the 2d corps and
Sheridan's cavalry were crossed over on the night of the 29th and moved
in front of Petersburg. On the morning of the 30th, between four and
five o'clock, the mine was sprung, blowing up a battery and most of a
regiment, and the advance of the assaulting column, formed of the 9th
corps, immediately took possession of the crater made by the explosion,
and the line for some distance to the right and left of it, and a
detached line in front of it, but for some cause failed to advance
promptly to the ridge beyond. Had they done this, I have every reason
to believe that Petersburg would have fallen. Other troops were
immediately pushed forward, but the time consumed in getting them up
enabled the enemy to rally from his surprise (which had been complete),
and get forces to this point for its defence. The captured line thus
held being untenable, and of no advantage to us, the troops were
withdrawn, but not without heavy loss. Thus terminated in disaster what
promised to be the most successful assault of the campaign.

Immediately upon the enemy's ascertaining that General Hunter was
retreating from Lynchburg by way of the Kanawha River, thus laying the
Shenandoah Valley open for raid into Maryland and Pennsylvania, he
returned northward and moved down that valley. As soon as this movement
of the enemy was ascertained, General Hunter, who had reached the
Kanawha River, was directed to move his troops without delay, by river
and railroad, to Harper's Ferry; but owing to the difficulty of
navigation by reason of low water and breaks in the railroad, great
delay was experienced in getting there. It became necessary, therefore,
to find other troops to check this movement of the enemy. For this
purpose the 6th corps was taken from the armies operating against
Richmond, to which was added the 19th corps, then fortunately beginning
to arrive in Hampton Roads from the Gulf Department, under orders issued
immediately after the ascertainment of the result of the Red River
expedition. The garrisons of Baltimore and Washington were at this time
made up of heavy-artillery regiments, hundred days' men, and detachments
from the invalid corps. One division under command of General Ricketts,
of the 6th corps, was sent to Baltimore, and the remaining two divisions
of the 6th corps, under General Wright, were subsequently sent to
Washington. On the 3d of July the enemy approached Martinsburg.
General