A turning point in U.S.-British relations came with the signing on August 9, 1842, of the Webster-Ashburton Treaty, which settled several matters between the two nations. The treaty took its name from Sec. of State Daniel Webster and Lord Ashburton, the British envoy in Washington. It adjusted the Maine-New Brunswick boundary, which had been the cause of the Aroostock War of 1838-1839. The U.S. received most of the territory in dispute as well as navigational rights on the St. John River. The treaty also settled the question of the U.S.-Canada boundary between Lake Superior and Lake of the Woods. As a result, the U.S. gained territory that included the rich Mesabi iron deposits discovered later. The two nations also agreed to cooperate in suppressing the slave trade. In a separate action Ashburton apologized for the Caroline affair, which involved the seizure in 1837 of the American-owned small streamer on the Niagara River.