This ruin (fig. 7), the largest in the canyon, is situated at the head of the South Fork. Although many of its walls have fallen, there still remains a semicircular great house (_B_, _C_, _D_) with high walls conspicuous for some distance. The ruin is a pueblo of rectangular form belonging to the pure type, showing circular depressions identified as kivas (_K_), embedded in collections of square and rectangular rooms, and massive walled buildings (_E_) on the south side. [Illustration: FIG. 7.—Ground plan of Hovenweep House.] The standing walls of the ruin are remains of a conspicuous D-shaped tower (_B_, _C_, _D_), which is multichambered. Its straight wall measures 23 feet, the curved wall 56 feet, and its highest wall, which is on the northeast corner, is 15 feet high. At the northwest angle of the ruin (A) there stand remains of high walls which indicate that corner of a rectangular pueblo. Hovenweep House (pl. 14, _a_) was the largest building in this canyon, but with the exception of the addition of a semicircular tower or great house, does not differ greatly from a pueblo like Far View House on the Mesa Verde. The piles of stone and earth indicating rooms below justify the conjecture that when the fallen débris is removed the unfallen walls will still rise several feet above their rocky foundations. If properly excavated, Hovenweep House would be an instructive building, but in its present condition, while very picturesque, its structure is difficult to determine. [Illustration: FIG. 8.—Ground plan of Hovenweep Castle.] HOVENWEEP CASTLE This ruin (pls. 14, _b_, _c_; 18, _b_), like the preceding, has circular kivas compactly embedded in rectangular rooms arranged about them, indicating the pure type of pueblos. The massive walled semicircular towers and great houses are combined with square rooms and kivas, indicating that it is distinguished by two sections, an eastern and a western, which, united, impart to the whole the shape of a letter L (fig. 8). WESTERN SECTION OF HOVENWEEP CASTLE