We must notice one point more: Each village of this nature, that was of any size, contained a larger ruin in the center. This was noticed in the ruins at Aztec Springs. This larger building was in the nature of a citadel, and there the inhabitants could retire when the approaches were carried by the enemy. This central building ultimately swallowed up all the others, and so developed into the pueblo structures we have noticed. The little walled inclosures surrounding the houses were largely in the nature of defenses. Tradition asserts that in many cases they were garden plats, and appearances sometimes confirm this. “They may also have been the yard proper for each family, in which the latter slept, cooked—in fact, lived—during the heat of the Summer months.”18 Referring once more to the ruins near the McElmo, we are told that every isolated rock and bit of mesa within a circle of miles of this place is strewn with remnants of ancient dwellings. We presume these were small, separate houses. They may have been outlying settlements of the tribe whose main village was at Aztec Springs. We must also notice the small tower in the corner. This was a watch tower. It was fifteen feet in diameter, walls three and a half feet thick, and in 1876 was still five feet high, It overlooked the surrounding country. The rainfall in the past must have been more abundant, to support the population we are justified in thinking once lived there. The nearest water is now a mile away, and during the dry season some fifteen miles to the north, in the Rio Dolores, and yet we have every reason to believe these old inhabitants were very saving of water. They built cisterns and reservoirs to store it up against the time of need. Tower on the Rio Mancos. We give a cut of the tower of the ruins of a similar village, or settlement, to the one just described, which occurs twenty miles to the southeast in the cañon of the Rio Mancos. Being so similar, we will mention it here. In this case the tower had only two walls. Mr. Holmes says the diameter of the outer wall is forty-three feet, that of the inner twenty-five feet. The space between the two circles is divided by cross-walls into ten apartments. This tower is placed also in the midst of a group of more dimly marked ruins or foundations, extending some distance in each direction from it. Mr. Holmes, however, states that there are no ruins of importance in connection with this tower, but that there are a number of ruins in the immediate vicinity. In this case, then, the citadel (if such it was) was not directly connected with other ruins.