392 KEPOET UNITED STATES GEOLOGICAL SURVEY. 



of resort, they could, in case of alarm, be reached with ease from within, 

 but be altogether secure from without. 



Figure 4. The large circular ruin, of which a ground-plan is given in 

 this plate, was also visited by Mr. Jackson, photographs were made, 

 and a brief description given ; but I deem it best to give a more de- 

 tailed description, the result of such observations and measurements as 

 could be made in a period of time entirely too short for a work of such 

 importance. 



This ruin is situated on a narrow strip of alluvial bottom about mid- 

 way in the cauon of the Mancos. On first approaching it, one does not 

 observe that it differs greatly from the ordinary fragmentary structures 

 below, as it is much decayed and almost hidden by artemisia and vines. 

 Closer inspection, however, develops the greater part of the outline, and 

 I imagine that a little excavation would bring all the foundations to 

 light. The inner wall can be traced throughout the entire circle, and is 

 in places 6 or 8 feet high. A portion of the outer wall, at the point far- 

 thest from the river, is still 12 feet in height and in a fair state of pres- 

 ervation. The space between the walls has been divided into cells, as 

 in the two examples given in Plate XXXI. Four of the cross- walls are 

 still a number of feet high, while others can be traced by lines of debris. 

 The diameter of the outer wall is 43 feet 5 that of the inner, 25 feet. 

 They are faced up with larger stones than usual (the heaviest of which, 

 however, could be lifted with ease by a single workman), and have been 

 filled in with rubble, adobe, and wood. The outside courses have been 

 dressed to the curve, and the implements used, judging from the appear- 

 ance of the picked surfaces, have been of stone. The main walls are 21 

 inches in thickness, while the partition-walls are somewhat lighter, and 

 seem to have been but slightly built into the circular walls. 



In order to determine the probable number of these cells, I measured 

 the two having complete walls, and found the inner side of each to be 

 8 feet. As these were both on one side of the circle, I had but to 

 measure the remaining space to complete the semicircle, and on so doing 

 found that there was just room for three additional cells and the neces- 

 sary partition-walls ; two of these were still traceable. To complete the 

 circle, therefore, ten apartments would be necessary. Being desirous 

 of confirming this conclusion, I took the diameter of the inner circle, 

 as given in my notes, and, by adding twice the thickness of the wall, 

 obtained a circumference of 89^ feet ; just sufficient space to accommo- 

 date ten apartments, with an equal number of partition- walls a fraction 

 less than 12 inches in thickness. 



By adding to the diameter of the inner circle the total thickness of 

 the walls, plus twice the distance between them, I obtained a diameter 

 of 43 feet for the outer circle. The circuit of the structure is, therefore, 

 135 feet. Although these figures are greater than those previously given 

 (estimated), I am confident that they cannot vary greatly from the truth. 



There were no indications of windows or doors in the fragment of 

 outer wall, but two nearly rectangular openings in the inner wall seem 

 to have served as door- ways between the central enclosure and the cells. 

 We may suppose that each cell had similar means of communication with 

 the interior. The one door way that remains entire is 6 feet from the 

 ground, and measures 2 feet in width by 3 in height. The stone-work 

 of the facing is very neat and exact, and the lintel is of a single slab 

 of sandstone. It may be fairly presumed that the outer wall had no 

 door-ways or windows within reach of the ground, and that entrance 

 was obtained, by means of ladders, through high windows or by way of 



