The subject of caches came up, so I'll put some original references here.
Basically a cache was a bell shaped hole dug somewhere dry and secure. Trade goods or furs would be put in the hole, then the hole covered and disguised.
Hopefully no one found the hole, and water didn't damage the goods buried.
Possibly the best description comes from W.A. Ferris' journal:
We made a cache on the nineteenth, of some goods, intended for future trading
with Crow Indians, who rove at some seasons, on the tract of country we are now passing. Cache,
derived from the French verb cacher, to conceal, is applied in this region to an excavation for
the reception of goods or furs, commonly made in the following manner. A proper place being
selected, which is usually near the border of some stream, where the bank is high enough to be
in no danger of inundation, a round hole two feet in diameter is carried down to a depth of three
feet, when it is gradually enlarged, and deepened until it becomes sufficiently capacious to contain
whatever is destined to be stored in it. The bottom is then covered with sticks to prevent the bales
from touching the ground, as otherwise they would soon contract moisture, become mouldy,
and rot. The same precautions are observed to preserve them intact from the walls of the cave.
When all is snugly deposited and stowed in, valueless skins are spread over the top, for the same
excellent purpose, and the mouth is then closed up with earth and stones, beat down as hard as
possible, to hinder it from settling or sinking in. The surplus earth taken out, is carefully gathered
up and thrown into the stream, and the cache finally completed, by replacing stones and tufts of
grass, so as to present the same uniform appearance, as the surrounding surface. If the cache is
made in a hard clay bluff, and the goods perfectly dry when put in, they will keep years without
damage.
Irving also gives us a thorough description of a cache, in his Astoria:
A cache is a term common among traders and hunters, to designate a hiding-place for provisions
and effects. It is derived from the French word “cacher”, to conceal, and originated among the
early colonists of Canada and Louisiana; but the secret depository which it designates was in use
among the aboriginals long before the intrusion of the white men. It is, in fact, the only mode
that migratory hordes have of preserving their valuables from robbery, during their long absences
from their villages or accustomed haunts, on hunting expeditions, or during the vicissitudes
of war. The utmost skill and caution are required to render these places of concealment invisible
to the lynx eye of an Indian. The first care is to seek out a proper situation, which is generally
some dry, low, bank of clay, on the margin of a water-course. As soon as the precise spot is
pitched upon, blankets, saddle-cloths, and other coverings are spread over the surrounding grass
and bushes, to prevent foot-tracks, or any other derangement; and as few hands as possible are
employed. A circle of about two feet in diameter is then nicely cut in the sod, which is carefully
removed, with the loose soil immediately beneath it, and laid aside in a place where it will be safe
from anything that may change its appearance. The uncovered area is then digged perpendicularly
to the depth of about three feet, and is then gradually widened so as to form a conical chamber
six or seven feet deep. The whole of the earth displaced by this process, being of a different color
from that an the surface, is handed up in a vessel, and heaped into a skin or cloth, in which it is
conveyed to the stream and thrown into the midst of the current, that it may be entirely carried
off. Should the cache not be formed in the vicinity of a stream, the earth thus thrown up is carried
to a distance, and scattered in such manner as not to leave the minutest trace. The cave, being
formed, is well lined with dry grass, bark, sticks, and poles, and occasionally a dried hide. The
property intended to be hidden is then laid in, after having been well aired: a hide is spread over
it, and dried grass, brush, and stones thrown in, and trampled down until the pit is filled to the
neck. The loose soil which had been put aside is then brought and rammed down firmly, to prevent
its caving in, and is frequently sprinkled with water, to destroy the scent, lest the wolves and
bears should be attracted to the place, and root up the concealed treasure. When the neck of the
cache is nearly level with the surrounding surface, the sod is again fitted in with the utmost exactness,
and any bushes, stocks, or stones, that may have originally been about the spot, are restored
to their former places. The blankets and other coverings are then removed from the surrounding
herbage; all tracks are obliterated; the grass is gently raised by the hand to its natural position, and
the minutest chip or straw is scrupulously gleaned up and thrown into the stream. After all this is
done, the place is abandoned for the night, and, if all be right next morning, is not visited again,
until there be a necessity for reopening the cache. Four men are sufficient, in this way, to conceal
the amount of three tons weight of merchandise in the course of two days. Nine caches were required
to contain the goods and baggage which Mr. Hunt found it necessary to leave at this place.
Ferris' journal also contains information about a man being killed while digging a cache:
A man in the employ of Smith, Sublette and Jackson, was engaged with a detached party, in constructing
one of those subterranean vaults for the reception of furs, already described. The cache
was nearly completed, when a large quantity of earth fell in upon the poor fellow, and completely
buried him alive. His companions believed him to have been instantly killed, knew him to be well
buried, and the cache destroyed, and therefore left him
Here's a line from Ferris about a cache being stolen:
We heard, in addition, that the Crows had discovered
a cache belonging to the same company, and robbed it; however, they must have been seen
while constructing it, or it could not have been properly closed; for a well made cache is in no
more danger of being discovered in these plains, than is any substance surrounded by the fibrous
effects of organic nature.
This is from Wilson Price Hunt's journal:
Our situation became critical. We had enough food for about five days. On the 31st Mr. Reed and
three others went downstream to try to get some horses and provisions from the Indians and to
learn if, below the spot that I had reached, it was possible to navigate the river. Sixteen men, with
four of our best canoes, went to attempt the passage. Then, because our lack of food prevented
any delay of our journeys we put to one side those things that were most needful to us and began
to dig holes in which to cache the remainder. Rain fell so heavily that we could not finish our
digging.
Another occurrence of a cache being opened and stolen, from Seton's Adventures:
They also informed us that the natives near Lewis river had shown them fowling-pieces, gun-flints,
lead, and powder; and that they had communicated this news to Mr. M’Kenzie, presuming that
the Indians had discovered and plundered his cache ; which turned out afterward to be the case.
