The employment of upright slabs of stone to mark graves probably prevailed to some extent in ancient practice, but other uses suggest themselves. Occupying a conspicuous point in the village of Kin-tiel (Pl. LXIII) is an upright slab of sandstone which seems to stand in its original position undisturbed, though the walls of the adjoining rooms are in ruins. A similar feature was seen at Peñasco Blanco, on the east side of the village and a short distance without the inclosing wall. Both these rude pillars are, in character and in position, very similar to an upright stone of known use at Zuñi. A hundred and fifty feet from this pueblo is a large upright block of sandstone, which is said to be used as a datum point in the observations of the sun made by a priest of Zuñi for the regulation of the time for planting and harvesting, for determining the new year, and for fixing the dates of certain other ceremonial observances. By the aid of such devices as the native priests have at their command they are enabled to fix the date of the winter solstice with a fair degree of accuracy. Such rude determination of time was probably an aboriginal invention, and may have furnished the motive in other cases for placing stone pillars in such unusual positions. The explanation of the governor of Zuñi for a sun symbol seen on an upright stone at Matsaki has been given in the description of that place. Single slabs are also used, as seen in the easternmost room group of Tâaaiyalana, and in the southwestern cluster on the same mesa, in the building of shrines for the deposit of plume sticks and other ceremonial objects. An unusual employment of small stones in an upright position occurs at Zuñi. The inclosing wall of the church yard, still used as a burial place, is provided at intervals along its top with upright pieces of stone set into the joints of a regular coping course that caps the wall. This feature may have some connection with the idea of vertical grave stones, noted at K’iakima. It is difficult to surmise what practical purpose could have been subserved by these small upright stones. Notwithstanding the use of large stones for special purposes the pueblo builders rarely appreciated the advantages that might be obtained by the proper use of such material. Pueblo masonry is essentially made up of small, often minute, constructional units. This restriction doubtless resulted in a higher degree of mural finish than would otherwise have been attained, but it also imposes certain limitations upon their architectural achievement. Some of these are noted in the discussion of openings and of other details of construction.