Action on the Division’s southern flank involved little more than hill climbing and foot races for the 1st Battalion, 1st Marines, and the Division Reconnaissance Company. After jumping off in the morning of D-plus 2, Lieutenant Colonel Hawkins’ infantry fanned out through a maze of twisting valleys and ridges. The battalion encountered only light resistance, which invariably evaporated under pressure, and by dark the assault elements had gained 4,000 yards. Hawkins then deployed his troops for night defense on the high ground south of 3/1’s positions overlooking the highway defile.[272] [272] McGee-Carlon interv, 9 Feb 55. On the right of the 1st Battalion, Captain Houghton’s Reconnaissance Company reached the tip of the Namdong Peninsula. The Recon troops spent two days, the 17th and 18th, patrolling this spacious tactical vacuum. A number of dispirited prisoners were collected and caches of arms and munitions uncovered. One of the more significant discoveries was a small arsenal in which Russian-type wooden box mines were being manufactured and stored in quantity. First encountered by Able Company engineers in the Pusan Perimeter, these crude but effective explosives would become serious obstacles to the Marine advance in the days ahead.[273] [273] HqBn, 1st MarDiv _Unit Rpts_, 9 Sep-11 Nov 50; and Houghton interv, 3 Aug 54. See also this series, I:225. The night of 17–18 September passed quietly for the 1st Marines. During the hours of darkness, Ridge requested intermittent naval gunfire to interdict Sosa and Hill 123, where he believed enemy defenses to be located. Jump-off fires were also planned for the morning in addition to air strikes. Captain P. W. Brock’s HMS _Kenya_ poured in more than 300 6-inch rounds with good results. “Our Royal Navy ally not only supported the battalion to the maximum of its naval gunfire desires,” said Ridge, “but volunteered to render more than was requested.”[274] [274] Ridge memo, 13 May 55. Shortly after first light on D-plus 3, the 2d Battalion attacked along the highway with Easy Company on the left of the road and Dog on the right. Premature air bursts from an artillery preparation resulted in two KIA and three WIA among the troops of Company E.[275] [275] 2/1 _SAR_, 6; Cunliffe interv, 24 Aug 54; Carter ltr, 9 May 55. Ridge’s 3d Battalion boarded a column of LVTs, DUKWs, and jeeps, then rumbled down the highway through 2/1’s assault companies. In striking contrast to the previous day’s advance, there was a conspicuous absence of NKPA infantry along the way. The Marines brushed aside light opposition, including an antitank roadblock at Sosa’s outskirts, and captured the town at noon. Covered by Baker Company Tanks, 2/1 moved into defensive positions on the right side of the railroad about a mile beyond the built-up area, and the 3d Battalion deployed on Hill 123 just across the tracks.[276] [276] _Ibid._; and 3/1 _SAR_, 7.