CAMP GIBBS, OREG., July 30, 1864.

SIR: In compliance with your directions that a scouting party be sent to Sheep Rock and its vicinity, I made a detail on the 21st instant of fifty men as follows: Second Lieutenant John F. Noble and sixteen men of Company G, twelve men of Company D, ten men of the detachment of Company B, and twelve men of the detachment of your own command left at this camp. The district of country to which the detachment was to march is but little known. The only information that I have ever been able to procure concerning it was from the Warm Springs Indians, to the effect that it was a barren desert. Its exact locality was unknown to any person of my command, and I had no guide to send out with the detachment. In consequence of these facts I determined to take command of the scouting party myself. Leaving camp on the morning of the 22nd instant, I proceeded along the timbered ridge immediately in rear of this camp in a course as nearly due west as the surface of the country would permit. I encamped the first night on a small tributary of Crooked River, about eighteen miles west of this camp. While descending the ravine upon which I encamped from the summit of the mountains, a single Indian was seen in the heavy timber of the canon. A pursuit was made, but he escaped in the thickets. As no signs of Indians were found in the vicinity, I concluded he was a hunter from some distant camp. From the camp my course was pursued due west to the big bend of Crooked River, where I encamped the second night. About fifteen miles west of this camp on Crooked River, on the open desert, stands a cluster of high peaked hills, isolated from any other range of mountains. I supposed this to be Sheep Rock. Accordingly on the morning of third day I continued the march westerly, following the course of Crooked River through the windings of the canon, six or seven miles to a point where the river makes a short turn of the north. Leaving the river at this point I marched directly west to this cluster of hilss, and arrmmit at 2 p. m. These hilss are high, rocky, and barren of vegetation except a few clusters of juniper. No water could be found on them, and I was reduced to the necessity of returning to Crooked River or of continuing on to the Des Chutes, about eighteen miles distant, as near as I could judge. I determined on the latter course, and resumed the march at 3 p. m., taking a course a little south of west, aiming to strike the Des Chutes at a point opposite to the Three Sisters. At 10 p. m. I arrived near the river, but did not succeed in reaching it that night. The bank of the river at this point is skirted with a strip of heavy pine timber and undergrowth; the surface of the ground very broken and rocky. In this labyrinth I became entangled in the dark, and notwithstanding the men and animals were famishing with thirst from a long and tiresome across the desert, I was obliged to halt for the night, having accomplished a march of thirty-five miles. During the night the men in squads of three of five found their way to the river and filled their canteens. The animals were tied up without water or grass.

On the morning of the 25th I proceeded down to the river and halted for the day. On the morning of the 26th the march was resumed. Going up the river three miles a good ford was found, and I crossed the river and proceeded down the river twenty miles and encamped on the west side. The following morning I recrossed the river and returned to Crooked River, intersecting our outward trail at the summit of the cluster of hills before mentioned. During a temporary halt here one of the men found a small spring about two miles north of the trail not large enough to water animals. A camp on Crooked River was reached