The purpose of cairns is explained in the novel when Okoya realizes why his turkey hunt was unsuccessful.
"Now I know why luck has failed me this morning! When I left our houses I should have scattered meal, and placed a pebble on the heap beside the trail, and offered a plume to our Mother Above. All this I neglected. Now I am punished for it by the birds concealing themselves..."
"Two little sticks, or twigs, placed crosswise and held to their place by a rock or stone, serve the same purpose in case of emergency. Such accumulations of rocks, little stone-heaps, are plentiful around Indian villages; and they represent votive offerings, symbolizing as many prayers. There were a number of them at the Rito around the big house, along the fields, and on the trails leading up to the mesa. Okoya went to the nearest one and placed two twigs crosswise on it, poising them with a stone. Then he scattered sacred meal, which he always carried with him in a small leather wallet, and thanked the Sanashtyaya, our mother, with an earnest ho-a-a, ho-a-a."
Now that I have read this, I notice that this propped stone at Bandelier looks like an effigy of a turkey or other fat game bird, surrounded by little clusters of stones. Of course it isn't Okoya's site, but other Indians may have used the site more recently.
The interior of Shotaye's cave dwelling was described in great detail.
"In the fireplace wood was smouldering, and a faint smoke rising from this found egress through a crude chimney. 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. Deer skins and cotton wraps were rolled in a bundle in another corner. Others were hung on a line made of rawhide and stretched across one end of the room, fastened to wooden pins driven into the soft rock. On the floor-to which a thick coating of mud, washed with blood and smoothed, gave a black, glossy appearance-there were beside, here a few stone axes with handles, there some black sooty pots, painted bowls, and finally the inevitable water-urn with wide body and narrow top, decorated in the usual style with geometrical and symbolical figures painted in red and black on whitish ground. The walls of the cave were burnished with burnt gypsum; the ceiling was covered by a thick coat of soot; and a band of yellow ocher, like wainscoting, ran along the base of the sides."
Interior of large caveate