When this document reached the troops, they had already crossed the Territorial line, and were prepared for its reception by the report of Captain Van Vliet as he passed them on his return to the States. Their position was embarrassing. In the absence of General Harney, each separate detachment constituted an independent command. The senior officer present was Colonel Alexander, of the Tenth Infantry, a thorough soldier in the minutiae of his profession, and distinguished by gallantry during the Mexican War. He resolved, very properly, in view of his seniority, to assume the command-in-chief until General Harney should arrive from the East. On the 27th of September, before the proclamation was received, the first division of the army crossed Green River, having accomplished a march of a thousand miles in little more than two months. That same night it hastened forwards thirty miles to Ham's Fork,--a confluent of Black's Fork, which empties into Green River,--where several supply-trains were gathered, upon which there was danger that the Mormons would make an attack. The other divisions followed within the week, and the whole force was concentrated. On the night of October 5th, after the last division had crossed the river, two supply-trains, of twenty-five wagons each, were captured and burned just on the bank of the stream, by a party of mounted Mormons led by a man named Lot Smith, and the next morning another train was destroyed by the same party, twenty miles farther east, on the Big Sandy, in Oregon Territory. The teamsters were disarmed and dismissed, and the cattle stolen. No blood was shed; not a shot fired. Immediately upon the news of this attack reaching Ham's Fork, Colonel Alexander, who had then assumed the command-in-chief, dispatched Captain Marcy, of the Fifth Infantry, with four hundred men, to afford assistance to the trains, and punish the aggressors, if possible. But when the Captain reached Green River, all that was visible near the little French trading-post was two broad, black rings on the ground, bestrewn with iron chains and bolts, where the wagons had been burned in _corral_. He was able to do nothing except to send orders to the other trains on the road to halt, concentrate, and await the escort of Brevet Colonel Smith, of the Tenth Infantry, who had started from the frontier in August with the two companies mentioned as having been left behind in Minnesota, and by rapid marches had already reached the Sweetwater. The condition of affairs at this moment was indeed critical. By the folly of Governor Walker's movements in Kansas the expedition was deprived of its mounted force, and consisted entirely of infantry and artillery. The Mormon marauding parties, on the contrary, which it now became evident were hovering on every side, were all well mounted and tolerably well armed. The loss of three trains more would reduce the troops to the verge of starvation before spring, in case of inability to reach Salt Lake Valley.