Sailboats going through rapids; Lieutenants H.J. Warre and Mervin Vavasour military reconnaissance expedition to Oregon Territory and BC.

In 1845-46, during the Oregon Boundary Dispute, Lieutenants Vavasour, and Henry Warre were dispatched on a mission to evaluate the logistics of a military campaign in the Columbia District (known then to Americans as the Oregon Country). Vavasour and Warre travelled in the guise of civilian fur traders through territory controlled by the Hudson's Bay Company (HBC), confidentially evaluating the strategic potency of both the land and the HBC's facilities. This information made its way back. to London in 1846