It was natural that the 1st Marine Division, with a zone of more than 15,000 square miles to control, should be ordered to occupy such an important road junction and potential assembly area as Majon-ni.[162] Thus the Marines of Lieutenant Colonel Thomas L. Ridge’s reinforced battalion were sent as a blocking and screening force. [162] Smith, _Notes_, 393–394; G-3 _SAR_, 5–6. _Marine Units Tied In for Defense_ In addition to H&S, Weapons, and the three rifle companies, the task organization consisted on 28 October of Battery D of the 2d Battalion, 11th Marines, the 3d Platoon of Company C, 1st Engineer Battalion, and detachments from ANGLICO, 1st Signal Battalion; Company D, 1st Medical Battalion; and H&S Company, 1st Marines.[163] [163] Except where otherwise indicated, this section is based on: Ridge, _Notes_; and Comments, 28 Feb 50; LtCol E. H. Simmons ltr, 14 Jan 56; 1stLt Charles R. Stiles, “The Dead End of Ambush Alley,” _Marine Corps Gazette_, xxxvi, no. 11 (Nov 51), 38–45. The battalion commander and his S-3, Major Joseph D. Trompeter, decided after a survey of the terrain that the commanding ground was too far from the village and too rugged for company outposts. The logical solution seemed to be a battalion perimeter combined with daytime company OPs and vigorous patrolling of the three main roads. In order to tie in all units of a perimeter 3770 yards in circumference, it was necessary to create provisional platoons of such H&S, artillery and engineer troops as could be spared from their regular duties. Even so, the defense was spread thin in places. The schoolhouse was the obvious place for the battalion CP. Communication within the perimeter was by telephone, with wires laid from the CP to artillery and mortar positions as well as company and platoon CPs. Radio communication was established with the regiment and the division but due to the terrain remained irregular at best. First Lieutenant Leroy M. Duffy and his engineers were assigned the task of constructing on OY strip on the east side of the perimeter which was completed on 2 November. A parallel cliff made it necessary to land planes at a dangerous angle, but no better site could be had in this steep-sided valley. [Illustration: MAJON-NI PERIMETER All roadblocks manned by Weapons Co. Perimeter between A and B manned by H&S Co, 3/1 and Btry D, 2/11, 28 Oct-4 Nov 50, by Able Co., 1/1, 5–7 Nov; and by H&S Co., 3/1, and Btry D, 2/11, 8–9 Nov. Perimeter between C and D manned by 3d Bn, KMC Regt, 10–14 Nov 50. MAP-6 ] Topography also limited Captain Andrew J. Strohmenger’s cannoneers, who were almost literally “firing out of a barrel.” Close-in support was out of the question in the bowl-like valley ringed with peaks, but the six howitzers were emplaced so that they could be swung to fire on any avenue of approach, especially toward the three roads leading into Majon-ni.[164]