HEADQUARTERS DISTRICT OF OREGON,
Fort Vancouver, Wash. Ter., June 19, 1862.

ASSISTANT ADJUTANT-GENERAL,

Headquarters Department of the Pacific, San Francisco, Cal.:

SIR: Since my last communication referring to the movement and disposition of troops east of the Cascade Mountains, I have the honor to report that a serious obstruction now exists to transportation between here and Fort Dalles. The extraordinary flood in the Columbia River has carried away a great portion of the railroad at Cascade Portage, on the Oregon side, destroying as well the bridges, and making otherwise impassable the wagon roads on this side. Meanwhile delay occurs from this cause to the early movement of Oregon cavalry and of the two companies of Washington Territory infantry under Major Rumrill now in readiness to march to Fort Colville. The season is already far advanced, and from the peculiar and lenghened severity of the past winter operations of every description throughout the district have been impeded. Transportation of supplies especially has been in every direction retarded. To accomplish successfully the designs of the commanding general for the employment of the Oregon cavalryin protective purposes east of Fort Walla Walla, it is emnently important that this regiment should at an early moment be concentions to this necessity, and arrangements have been made in furtherance of the general plans contemplated with the transportation and portage companies to repair the damages to roads, and press forward in advance of all others the supplies and troops required by the Government. The cavalry companies will be sent in advance and at the earliest moment that the transit is practicable. Immediately after assuming command of the district I directed full and complete returns to be made tothese headquarters from each post of the property on hand, with the view, among other purposes, to ascertain the amount of transportation available beyond the ordinary garrison requirements. Adopting the plan heretofore practiced at Fort Walla Walla, and as I am informed contemplated the coming season, there will be ianimals to firt our the expeditions to the mining country and on the emigrant trail east. On this subject I have directed a full and detailed report from the commanding officer at Fort Walla Walla, whose views when received will be forwarded for the consideration of the commanding general. Fort Colville can provide its own transportation if the route now proposed is adopted, viz, to have the troops and supplies sent by steamer to the mouth of Palouse on Snake River, thence by their own teams. This mode after full investigation I reommend as the quickest, safest and most economical. All the surplus transportation at the depot will be shipped to Fort dalles and used with what is not required at this latter post to convery the subsistence for the cavalry on the march to Fort Walla Walla. Application has recently been made for a detachment of troops at the Warm Springs Indian Reservation In the change that the large emigration to the whole country east of the Cascade Mountains ill effect in the disposition of troops and the claims for protection, the necessity for compliane with this request is not clear. To provide for such requirements, however, sufficient transportation will either be retained or returned from Fort Walla Walla to send the requisite force and keep it supplied. A large number of public animals have within the pastyear been removed from the district, and at Fort Walla Walla especially casualties in the means of transportation have been during the past winter serious and numerous. The posts on this side of the Cascade Mountains will be brought