12 June proved to be the toughest day for the Argentine Marines. From the moment the 2nd Battalion Scots Guards had finally been moved to Goat Ridge by helicopter, 1,500 rounds of artillery, descended upon the Marines, in preparation for the coming infantry assault. At the same time 3 PARA on Mount Longdon came under heavy and accurate fire that killed four Paras and one REME craftsman and wounded seven Paratroopers in the shelling that was directed by Sub-Lieutenant Marcelo de Marco, the artillery officer of the 5th Marines on Tumbledown Mountain.