HEADQUARTERS,
Foret Yuma, November 12, 1861.

Lieutenant Ben. C. CUTLER,

Actg. Asst. Adjt. General, Southern Dist. of California, Los Angeles:

LIEUTENANT: In accordance with a personal communication from the colonel commanding the Southern District of California, I submit the following statements as to the defenses and supplies of this post:

Defenses. -Some delay has been involved in getting possession of all the boats upon the river. There is a boat at Gonzales' Ferry, some thirty miles below this post, which I shall have in my possession within the next forty-eigh hours, either by negotiation or seizure. Another boat is kept by a man named Winegar, sixteen miles above here. I shall take steps to have it secured as soon as possible. All others on the river are in my possession except the steamer which has been absent twenty-four hours over time on atrip to the mouth of the river for supplies. I am assured of the loyalty of the steam-boat men, and see no reason to question it. It is manifestly so much to Mr. Yager's interest to be faithful to the United States Government that I credit his assertions to that effect. He has co-operated with me in all my efforts to promote security. Whenever theere is any doubt about the fidelity of any person I require them totake th eoath of allegiance. This and keeping them watched is all that I can do until I have proper grounds for takign them into custody. The Colorado is very low, but there are really no fords upon it that can be used by an armed force. A few travelers may partially wade and swim acorss in one or two places, but no munitions of war could be crossed in that way. The reported ford at the mouth of the river remains yet to be inquired into. Rafts coudl be constructed on the left bank out of cottonwood and other trees, and should the enemy resort to that method at any point properly removed from this post I am at a loss t counteract it. Little has yet resulted from my communication with the Indians. I have had some informal interviews with one or two of the chief Yumas, and am to have a grand talk on the coming Sunday. As yet I have formedno high opinion of their efficiency as allies. The cicruit of the Yumas is limited. They are at war with the Maricopas and Pimas, consequently will not venture into the country whence our enemies are expected, and the same cause prevents the receipt of news from the last-mentioned tribes. I shall spare no effort toward being kept properly informed with such means as I can command. But I shall mainly rely for defense upon constant vigilance and preparation. In the latter respect every thing is to be done-organization, temporary field-works, preparation of ordnance and ammunition, drill of artillery detachments, &c. Without wishing to cast any relfections upon the command which preceded the present garrison, I cannot forbear the remark that avery great improvement in its late defense has been found necessary. Two 12-pounder or 18-pounder pieces with the requisite ammunition would add t the strength of the post, and I recommend that they be sent here as soon as possible.

Medical department. -The post surgeon states officially that the medical suppies are ample for 300 men until May 1, 1862. Healso has called my notice to the necessity of issues of antiscorbuties. By my direction the acting commissary of subsistence has purchased one month's supply of potatoes, to be issued in accordance with Revised Army Regulations, but no such opportunity is likely to offer again, and steps should be taken to supply the command either by sea or land