This was built over the hearth, with two vertical side slabs of pumice supporting a perforated square flag, over which a primitive flue, made of rubble cemented by mud, led to a circular opening in the front wall of the cave.

In a corner stood the frame for the grinding-slabs, or _metates_, and in it the three plates of lava on which the Indian crushes and pulverizes his maize were placed in the convenient slanting position.

Not only the prismatic crushing-pins, but freshly ground meal also, lay in the stone casings of the primitive mill, and on these the plates themselves.

Deerskins and cotton wraps were rolled in a bundle in another corner.

Others hung on a line made of rawhide and stretched across one end of the room, fastened to wooden pins driven into the soft rock.