Here's one account:
During the 1876 campain against the Sioux and Cheyenne Indians in the west, the War Department leased the Missouri river steamer Far West as a supply ship to serve the troops. The Far West was loaded with 200 tons of supplies and equipment for the commands operating in the Big Horn country. Captain Grant Marsh was commissioned to take the vessel up the Yellowstone river to the Big Horn, then up the Big Horn to the mouth of the Little Big Horn river. Here he was to anchor and wait the arrival of General Terry's troops who were to recieve the supplies. Captain Marsh was instructed to be in position at the Little Big Horn by June 26, 1876.
Captain Marsh anchored about 20 miles up the Big Horn river at what he thought was the mouth of the Little Big Horn river and settled down to wait. On the following morning, two freight wagons drawn by mules pulled up at the river's edge opposite the Far West. One of the three men hailed the vessel and was rowed out to her. The man explained to Marsh that he was in charge of the wagons which operated for a freighting company out of Bozeman, Montana. He and his companions were on route to Bismarck N.D. with a cargo of gold.Since they had had several narrow escapes from indians, the man asked Captian Marsh to take the gold aboard and deliver it in Bismark on his trip back down the Missouri.
When Marsh wanted to know the value of the gold, he was told it was $800,000., packed in buckskin bags. Reluctant to assume responsibility for such cargo, Marsh explained that he was under orders from the War Department and could not set a date for arrival in Bismarck. He finally agreed, however to help the freighters and had the gold transfered to his ship. The freighters headed back to Bozeman and were never seen alive again.
The next moring, curls of smoke from behind the hills in the distance suggested a large indian encampment. Uncertain that he was anchored at the mouth of the Little Big Horn, and fearing that the indians might attack his vessel, Captain Marsh unanchored and steamed back down the the Big Horn to a safer anchorage. He then ordered the gold to be rowed ashore and buried some distance inland.
On the morning following the burial of the gold, the Far West returned to the mouth of the Little Big Horn and anchored again. It was there that the crew learned from a Crow indian scout of the massacre of Custer's command on June 25, 1876. Soon afterward General Terry ordered Marsh to take aboard the wounded from Reno's and Benteen's commands and transport them to Bismarck. In the urgency of the situation, the buried gold was forgotten.
With 50 or 60 wounded soldiers aboard, the Far West started the hazardous journey down the Big Horn, followed by bands of hostile Sioux running along the banks. Reaching the Yellowstone river, Marsh anchored and awaited the arrival of Terry's forces which he was instructed to ferry across the river. It was not until the morning of July 3rd that the Far West began the 700 mile trip to Bismarck. Upon it's arrival there, the first news of the Custer Massacre was released to the world.
Some years later, after Marsh had given up command of the Far West, he is said to have gone to Bozeman to inform the freighting company where the gold entrusted to him was buried. He also learned that the three men had never returned to Bozeman. They were presumably casualties of an indian attack. Similar freighting losses had forced the company out of business. So far as it is known, neither Captian Marsh nor any of the men who had participated in the burial of the gold ever tried to recover it.
There may be other versions out there?