FORT GASTON, CAL., March 19, 1864.

SIR: I have the honor to transmit herewith the following report:

According to instructions from the commanding officer, I left this post at 8. 30 a. m. of the 9th with six men of Company A, First Battalion Mountaineers, California Volunteers, and was accompanied by Lieutenant Hackett and thirty-five men of Company G, Sixth Infantry California Volunteers, with ten days' rations. Marched eighteen miles and camped on a flat on Redwood Creek, near Camp Anderson. March 10, crossed Redwood Creek at 8 a. m., and at 2 p. m. came to Blad Mountain, where I halted until sundown in order to proceed unobserved to Thief Camp, where the balance of my detachment was stationed. Reached there at 10 o'clock at night; distance about twenty-two miles. March 11, remained in camp and prepared two days' cooked rations whilst the scouts were out reconnoitering. March 12, started about 5 a. m., in order to cross over the bare ridge before sunrise. Marched twelve miles and halted ina ravine, where we camped and sent scouts in different directions. March 13, crossed back on the same ridge, and sent one corporal, two privates, and an Indian scouting down Redwood Creek. The rest of the detachment marched to what is called Hempfield's ranch and camped. The scouts came in and reported having found three ranches, the Indians having left some three days before. March 14, I left camp at sunrise with ten men of my command and six men of Company G, Sixth Infantry California Volunteers, proceeding across the country. Crossed Redwood Creek about seven miles above the upper crossing. Lieutenant Hackett took the train and the balance of the men and advanced on the trail to meet me at what is called Bloody Camp; distnace about twenty-two miles. March 15, left camp at 3 o'clock in the morning with twenty men from my command and twenty-five from Company G, Sixth Infantry California Volunteers, en route to the mouth of South Fork of Trinity River, passing over the ground where I had an engagement with the Indians. They had been back to bury their dead. Crossed the head of Willow Creek, and reached the mouth of the South Fork of Trinity River at 6 p. m. Traveled thirty-five miles. Lieutenant Hackett took the train and the balance of my command and advanced on the trail to meet me at the mouth of the South Fork of Trinity River, where he arrived after marching twenty-five miles. March 16, remained in camp and sent scouts in different directions; also some hunters to kill a beef, as our pork was all gone. The hunters did not succeed in finding any cattle. The scouts returned at 3 o'clock in the evening, reporting having found a ranch consisting of five bark houses, which they think was vacated some twelve hours before they found them. They left several articles of soldiers' clothing, which had been worn out. The Indians seem from the sign to be traveling in the direction of a place on Trinity River called Burnt Ranch. Everything that was left behind in their flight was burnt, also their ranches. March 17, Lieutenant Hackett took the train and all the men but two and went down the Trinity River to the mouth of Willow Creek. I took the two remaining men and advanced over the Willow Creek Mountain, from thence down Willow Creek to the mouth, where I joined my command and camped for the night; also sent some men to kill a beef, in which they succeeded; also found a stray hose running with the cattle. March 18, I made a raft and sent a corporal, an Indian, and private across the Trinity River for the purpose of reconnoitering some Indian houses. The corporal reported seeing the houses, but did not deem it prudent to approach them up the ravine, and to get to them by going up on the mountain would consume the greater portion of the day, and knowing that the