Although some of the rooms and walls seen by the first white settlers in the valley have now collapsed, evidence of at least three stories is still clearly visible in several places in the ruin. The main part consists of three sides of a rectangle with a slightly bowing outer wall on the fourth side, composed of single rooms, which seals off the central plaza. The only entrance into the pueblo was the one along the path by which visitors enter the ruin today. The pueblo was built of yellowish-brown and tan sandstone blocks, most of them shaped into rectangles by pecking or grinding. To support the weight of the upper rooms, the lower walls are much thicker and are composed of rubble fill with an outer veneer wall of the better shaped rectangular blocks. In many places, the spaces between them are filled with small chinking stones set in adobe mud. Sometimes broken pieces of pottery vessels were used for spalls. Originally, the walls were plastered with layers of adobe, most of which, unfortunately, have eroded away. [Illustration: Section of wall at Aztec Ruins showing a band of green sandstone.] One unusual feature in the West Ruin consists of two very fine bands of green sandstone blocks which extend horizontally along the west outer wall of the pueblo and into a few of the interior rooms of the southwest corner. There are indications in a few places that originally there may have been three such parallel bands. The north and northwest sides of the ruin contain the most extensive building remains. The highest walls and best construction still exist there, and one can see evidence of at least three stories. Also in the north portion, along the extreme back row of rooms at the ground level, there is a series of seven rooms, each of which has its original ceiling intact. These seven were the first entered by early relic hunters, who found most of the original doorways to the south sealed up and who broke through the walls of each room in an easterly direction. These breaches in the walls have been repaired but left open, so that today you can go from one room to the next along the path taken by the early explorers rather than through the doorways used by the Indians. From the plaza, the Indians gained access to these northwestern rooms by entering the west side rooms. Then, turning at right angles, they proceeded northward through the doorways and rooms until they reached the final row of rooms at the north.