Although burials are commonly found in the refuse heaps associated with the small dwellings of Chaco Canyon, the majority of the dead of the great communal houses have never been found. Occasional burials have been found but not enough to account for even five per cent of the deaths which must have occurred during the period of occupation. Many of the graves which have been found in abandoned rooms had already been looted by pre-archaeological grave robbers. The few undisturbed interments which have been discovered suggest that grave offerings were extremely rich, and, with such an incentive, archaeologists have searched far and wide for the ancient cemeteries, but, as yet, without success. There is no indication that cremation was practiced, so there is still hope that some day we may find the spot where the ancient people laid the dead to rest, and so learn more of their arts and crafts. Some idea of the remarkable finds which may yet be made may be gained from a burial found in Ridge Ruin, a Great-Pueblo site about twenty miles east of Flagstaff, Arizona.[88] Here was found the body of a man interred with over six hundred articles, many of which show the most remarkable workmanship. They included pottery, beautiful baskets, fine turquoise mosaics, stone and shell ornaments, and hundreds of finely flaked arrowheads. This was of course an unusual burial, and many of the offerings were ceremonial objects such as would be placed in a grave only under extraordinary circumstances, but it gives some idea of the wealth of material which may yet be found and which will contribute to our knowledge of the ancient Pueblo culture. The great dwellings of Chaco Canyon apparently were abandoned in the twelfth century, and there is no doubt a fascinating story connected with the abandonment of these huge buildings which were erected with so much labor and finished with such care. It is a story which we do not yet fully understand, and, to a great extent, we can only guess at the causes which underlay the migration. It was probably the first phase of the general movement which eventually involved the entire population of the northern part of the Southwest, but it is even more difficult to account for than some of the later migrations, for there were no particularly severe droughts at this time. There were some dry years, however, which may have led to disastrous arroyo-cutting.