美國方面，由當時在北京的美國駐華公使蒲安臣，指派駐廈門領事李仙得（Charles W. le Gendre）為美國外交代表，偕同通事六人，於9月4日扺臺，9月10日會合台灣總兵劉明燈率兵士500員隨行，越過番界，於9月23日深入琅𤩝。之後李仙得以劉明燈部隊留守後方繼續前行。1867年10月10日，李仙得於今恆春城外的出火面會瑯嶠十八社總頭目卓杞篤，雙方達成口頭協議；美國表示對瑯嶠十八社的友好，如果原住民秉持人道精神不再殺害海難生還者，美國不會再出兵；而卓杞篤亦釋出善意，保證不殺害將來以紅旗作識別求援的海難生還者，是為「南岬之盟」。
At the request of Tauketok, the ruler of the eighteen tribes south of Liangkiau, and between the range of hills east of it and the Eastern Sea including the bay known as the Southern Bay of Formosa where the crew of the American bark Rover were murdered by the Koaluts, I, Charles W. Le Gendre, United States consul for Amoy and Formosa give this as a memorandum of the understanding arrived at between myself and the said Tauketok in 1867, the same having been approved by the United States Government and assented to, I believe by the foreign ministers at Pekin viz:
Cast-aways will be kindly treated by any of the eighteen tribes under Tauketok. If possible, they are to display a red flag before landing.
Ballast and water. - Vessels requiring supplies are to send a crew on shore, displaying a red flag, and must not land until a similar token has been shown from the shore, and then only at the spot indicated. They are not to visit the hills and villages, but, when possible, are to confine their visit to the Tuiahsockang, being the first stream on the east coast north of the southeastern cape of South Bay, and to the Toapangnack, to the west of the rock where the Rover's crew were murdered, the latter being the better watering place in the northeast monsoon. Persons landing under other than these conditions do so at their own peril, and must not look, I believe, for protection from their government if molested by the natives, who in such case will not be held responsible for their safety. CHAS. W. LE GENDRE, United States Consul.
Witness: I. ALEX. MAN, Commissioner of Customs for Southern Formosa.
Witness and interpreter: W. A. PICKERING
^見李仙得〈1867年11月8日呈給美國公使的報告，現藏U.S. National Archives: CD, Despatches from U.S. Consuls in Amoy, China, 1844-1906, M-100, R-3。節選自陳政三. 〈李仙得將軍與卓杞篤酋長〉. 原住民族文獻. 2013年12月, (第12期) [2021-09-16]. （原始内容存档于2021-09-16）.
