ets, the workmen packing
and shaping the ridge by pressure from their limbs as they stand astride
of the row. In this way the ridges are made as high or somewhat higher
than their breadth at the base, and quite near together, so that there
is just room in many cases to walk between the beds. In one cave in
America, where the ridge system is used to some extent, the ridges are
made with the aid of a board frame the length of the bed and the width
of the base of the ridge. The long boards of this frame are slanting so
that they are more or less the shape of the ridge, but not equal to its
height. This frame is placed on the rock bottom, filled with manure and
tramped on by the workmen. Then the frame is lifted on the ridge and
more material is added and tramped on in like manner, until the bulk of
the ridge bed is built up in this way and compressed into shape.

=Beds in Houses Constructed for the Purpose of Growing
Mushrooms.=--Where only the floor of the house is used, a middle bed and
two side beds are sometimes formed in the same manner as described in
the construction of the house for the tiers of beds, with an alley on
either side of the large center bed, giving access to all. In some cases
the entire surface of the bottom is covered with material, but divided
into sections of large beds by framework of boards, but with no alleys
between. Access to these beds is obtained by placing planks on the top
of the boards which make the frame, thus forming walks directly over
portions of the bed. In some cases ridge beds, as described for cave
cultivation, are made on the floor of these houses. The beds are filled
in the same way as described for the cave culture of mushrooms, but
usually, in the beds made in houses built for the purpose of growing
mushrooms, a percentage of soil is mixed in with the manure, the soil
being usually mixed in at the time of turning the manure during the
process of fermentation. Garden soil or rich loam is added, say at the
first time the manure is turned while it is fermenting. Then, some time
later during the process of fermenting, another admixture of soil is
added. The total amount of soil added is usually equal to about
one-fifth of the bulk of the manure.

As this material, formed of the manure with an admixture of soil, is
placed in the beds it is distributed much in the same manner as
described for the making of flat beds in caves or tunnels. Usually,
however, if there is coarse materia