main source of supplies. But the great difficulty is in supplying the interior posts, which can be reached from the Colorado River only by crossing barren and sandy deserts, where there is great scarcity of water for men and animals. The natural line of supply for Las Calabasas and Tucson and their dependencies is from some port on the Gulf of California, and it is of the greatest importance for the future prosperity of Arizona that some good port should be obtained in the gulf. It is hoped that this matter will be kept constantly in view in all future negotiations with Mexico. The boundary line should at least be carried so far south as to include the port of La Libertad. From that point to Las Calabasas the rotue is short and easy for the transportation of supplies.

TROOPS.

I must again urge upon you the necessity of sending a cavalry force to this division. We have now no mounted troops in Washington, Oregon, Idaho, and Nevada, and in California and Arizona only the California volunteers, who regard their term of enlistment as having expired and wish to be mustered out. These troops are made up of most excellent meterial, but men who regard themselves as unjustly retained in service will not be very efficient in the field. You will bear in mind that when your orders for mustering out the volunteers are completely carried out, the only forces in this entire division will be the Second Artillery and Ninth and Fourteenth Infantry. The Ninth is only a small regiment. The artillery will be required to garrision the forts on the coast, and the Ninth Infantry in the interior of California and Nevada.

This leaves only one battalion of the Fourteenth Infantry for the Department of the Columbia and two battalions for Arizona. The hostile character of the Indians in the latter Territory requries more posts and larger gerrisons than in Oregon, Washington, and Idaho; but circumstances may render it necessary to re-enforce the troops in the latter department. With the present forces in the division it would be difficult to do this without seriously exposing other district to Indian depredations. A regiment of cavalry would do much to relieve this embarrassment. The accompanying report of Major-General McDowell will explain the necessity of retaining certain volunteer troops for the present. It also contains a list of those mustered out.

Very respectfully, your obedient servant,

H. W. HALLEKC,

Major-General, Commanding.