<P> The third phase of the battle came as Rodes renewed his assault from the north and Heth returned with his entire division from the west, accompanied by the division of Maj. Gen. W. Dorsey Pender . Heavy fighting in Herbst's Woods (near the Lutheran Theological Seminary) and on Oak Ridge finally caused the Union line to collapse . Some of the Federals conducted a fighting withdrawal through the town, suffering heavy casualties and losing many prisoners; others simply retreated . They took up good defensive positions on Cemetery Hill and waited for additional attacks . Despite discretionary orders from Robert E. Lee to take the heights "if practicable," Richard Ewell chose not to attack . Historians have debated ever since how the battle might have ended differently if he had found it practicable to do so . </P> <P> On the morning of July 1, Union cavalry in the division of Brig. Gen. John Buford were awaiting the approach of Confederate infantry forces from the direction of Cashtown, to the northwest . Confederate forces from the brigade of Brig. Gen. J. Johnston Pettigrew had briefly clashed with Union forces the day before but believed they were Pennsylvania militia of little consequence, not the regular army cavalry that was screening the approach of the Army of the Potomac . </P> <P> General Buford recognized the importance of the high ground directly to the south of Gettysburg . He knew that if the Confederates could gain control of the heights, Meade's army would have a hard time dislodging them . He decided to utilize three ridges west of Gettysburg: Herr Ridge, McPherson Ridge, and Seminary Ridge (proceeding west to east toward the town). These were appropriate terrain for a delaying action by his small division against superior Confederate infantry forces, meant to buy time awaiting the arrival of Union infantrymen who could occupy the strong defensive positions south of town, Cemetery Hill, Cemetery Ridge, and Culp's Hill . Early that morning, Reynolds, who was commanding the Left Wing of the Army of the Potomac, ordered his corps to march to Buford's location, with the XI Corps (Maj. Gen. Oliver O. Howard) to follow closely behind . </P> <P> Confederate Maj. Gen. Henry Heth's division, from Lt. Gen. A.P. Hill's Third Corps, advanced towards Gettysburg . Heth deployed no cavalry and led, unconventionally, with the artillery battalion of Major William J. Pegram . Two infantry brigades followed, commanded by Brig . Gens . James J. Archer and Joseph R. Davis, proceeding easterly in columns along the Chambersburg Pike . Three miles (5 km) west of town, about 7: 30 a.m., Heth's two brigades met light resistance from cavalry vedettes and deployed into line . Eventually, they reached dismounted troopers from Col. William Gamble's cavalry brigade . The first shot of the battle was claimed to be fired by Lieutenant Marcellus E. Jones of the 8th Illinois Cavalry, fired at an unidentified man on a gray horse over a half - mile away; the act was merely symbolic . Buford's 2,748 troopers would soon be faced with 7,600 Confederate infantrymen, deploying from columns into line of battle . </P>

Why was it important that the union held on to the high ground in gettysburg