The time the author could give to his visit to the Mud Spring Ruin (pl. 3, _b_) was too limited to survey it, but he noticed in addition to the two circular buildings already recorded, a large mound situated on the west side of the gulch, and numerous small mounds on the east side of the same, each apparently with a central depression like a kiva. All these mounds have been more or less mutilated by indiscriminate digging, but many mounds, still untouched, remain to be excavated before we can form an adequate conception of the group. The “triple-walled tower” is now in such a condition that the author could not determine whether it was formerly circular or D-shaped; the “small tower” is in even worse condition and its previous form could not be made out. The Mud Spring mounds cover a much larger area than descriptions or ground plans thus far published would indicate. Originally Mud Spring Ruin consisted of a cluster of pueblos of various sizes, each probably with a circular kiva and rectangular rooms, combined with one or more towers at present too much dilapidated to determine architectural details without excavations. Like the other clusters of pueblos in the McElmo and Montezuma Valley, the cemetery near Mud Spring Ruin has suffered considerably from pothunters, but there still remain many standing walls that are well preserved. RUIN WITH SEMICIRCULAR CORE This ruin is situated on the San Juan about 3 miles below the sandy bed of the mouth of the Montezuma, on a bluff 50 feet above the river. The ground plan by Jackson[21] indicates a building shaped like a trapezoid, 158 feet on the northeast side, 120 on the southeast, and 32 on the northwest side. The southwest side is broken midway by a reentering area at the rim of the bluff over the river. [21] Tenth Ann. Rept. U. S. Geol. Surv. Terr. (Hayden Survey) for 1876, pl. xlviii, fig. 2, 1879. In the center of this trapezoidal structure there is represented a series of rooms arranged like those of Horseshoe House, but composed of a half-circular chamber surrounded by seven rooms between two concentric circular walls. Thus far the homology to Horseshoe House is close but beyond this series of rooms, following out the trapezoidal form, at least five other rooms appear on the ground plan. The position of these recalls the walls arranged around the tower at Mud Spring village. In other words, the ruin resembles Horseshoe House, but has in addition rectangular rooms added on three sides, forming an angular building. So far as the author’s information goes, no other ruin of exactly this type, which recalls Sun Temple, has been described by other observers. WOLLEY RANCH RUIN Wolley Ranch Ruin, situated 10 miles south of Dolores, is one of the largest mounds near Cortez. There are evidences of the former existence of a cluster of mounds at this place, only one of which now remains. This is covered with bushes, rendering it difficult to trace the bounding walls. BLANCHARD RUIN