angular ruin, containing three well-marked apartments. Its walls are 

 6 or 7 feet Mgb, and, unlike those of the preceding examples, do not 

 coincide with the cardinal points. South of this, and occupying the 

 extreme southern end of the terrace, are a number of small circles and 

 mounds, while an undetermined number of diminutive mounds are dis- 

 tributed among the other ruins. 



To the east of the Indian trail, as shown in the plate, are a number of 

 inclosures of lesser importance, which, from want of time, were not 

 closely examined. 



Nowhere about these ruins are there any considerable indications of 

 defensive works, and the village, which is scattered over an area fully two 

 miles in circuit, has no natural advantages whatever. Neither are there 

 traces of ditches, nor of anything that might throw important light upon 

 the habits or occupations of the people. A few arrow-heads and mi- 

 nute cutting-implements were picked up. Countless chips of jasper, 

 obsidian, and tiint were scattered around, and the soil was literally full 

 of fragments of painted and ornamented pottery. 



On the opposite side of the river, and at intervals above and below, 

 are isolated groups of ruins and heaps of debris — certainly the remains 

 of dwellings. These seeui to have been distributed very much as dwell- 

 ing-houses would be in the rural districts of civilized and peaceable 

 communities. 



It is possible that there are undiscovered ruins on this stream equally 

 important with that described; for, in pursuing my geologic investiga- 

 tions, I was compelled to take a long detour to the westward from this 

 point, returning to the La Plata again a few miles above its junction 

 with the San Juan. On this occasion, while riding through a desert- 

 like locality, quite naked and barren, much resembling the well-known 

 Mauvaises terres, I was surprised to observe fragments of pottery strewn 

 around, and presently a number of ruins, in a very reduced state and 

 almost covered by the drifting sand, and this six or eight miles from water. 

 On the high, dry table-lands, on all sides, fragments of pottery were 

 picked up. What could have induced people to build and dwell in such 

 a locality it is useless to surmise. 



GROUP OF CAVE-DWELLINGS AND TOWERS ON THE RIO SAN JUAN. 



Plate II. 



On the San Juan Eiver, about thirty-five miles below the mouth of the 

 La Plata and ten miles above the Maucos, occurs the group of ruins 

 figured in Plate II. 



The river is bordered here by low lines of bluffs formed from the more 

 compact portions of the Middle Cretaceous shales. At this particular 

 place, the vertical-bluff face is from 35 to 40 feet in height. 



I observed, in approaching from above, that a ruined tower stood 

 near the brink of the cliff, at a point where it curves outward toward 

 the river, and in studying it with my glass detected a number of cave- 

 like openings in the cliff-face about half-way up. On examination, I 

 found them to have been shaped by the hand of man, but so weathered 

 out and changed by the slow process of atmospheric erosion that the 

 evidences of art were almost obliterated. 



The openings are arched irregularly above, and generally quite shal- 

 low, being governed very much in contour and depth by the quality of 

 the rock. The work of excavation has not been an extremely great 



