HOLMES.] CLIFF-HOUSES, RIO MANGOS. 391 



CANON OF THE KIO MANGOS. 



Fifteen miles from its junction with the San Juan, this stream emerges 

 from the southwest border of the Mesa Verde, through which it has cut- 

 its way, producing a most remarkable canon. This canon has already 

 been once or twice described; but, in order to make my subsequent 

 descriptions better understood, I shall give here an outline. The Mesa 

 Yerde is a somewhat irregular table-land, comprising an area of about 

 seven hundred square miles, and is formed of a great series of nearly 

 horizontal sedimentary rocks, of which the surrounding country has> 

 been denuded. This series of strata consists, in the upper part, of 

 massive sandstones ; in the middle part, of alternating sandstones and 

 shales; and in the lower one thousand feet, chiefly of shales and clay. 

 These softer beds are, when once exposed to the erosive agents, carried 

 away with great rapidity, and, as a consequence, the firmer rocks above 

 are undermined and break down in vertical cliffs, and, where soft and 

 hard beds alternate, a series of steps, with intervening slopes, is formed. 

 It will readily be seen that a canon thus formed would consist in gen- 

 eral of a narrow, irregular river-bottom, long steep slopes of debris ris- 

 ing like the arms of a letter V from this, then a succession of steeps and 

 slopes, culminating above in a series of lofty, embattled cliffs. The 

 canon is nearly thirty miles in length, and ranges from one to two thou- 

 sand feet in depth. It seems to have been a favorite resort of the cliff- 

 building people, and ^/racesof their industry may be found everywhere, 

 along the bottoms, in the cliffs, and on the high, dry table-lands above. 



The six following plates will be taken up in the delineation of the 

 more interesting portions of these remains. 



PLATES XXXIII AND XXXIV. 



Figure 1, Plate XXXIII, illustrates the method of walling up the 

 cave-fronts as described on a preceding page. This sketch was made at 

 the last-mentioned locality on the E.io Mancos. The group occurred in 

 the cliff about thirty feet from the base. The three door-ways opened 

 into as many small apartments, and these were connected with each 

 other by very small passage-ways. The farther door could not be 

 reached from the outside, as the platform of rock had broken away* 

 See foreground in Plate XXXII. 



Figure 2 gives a plan of the double tower near the mouth of the Man- 

 cos ; it has already been described. 



The ruin, of which apian is given in Figure 3, occurs on the left bank 

 of the Mancos about eight miles above the foot of the canon. It is one 

 of the best preserved specimens of the ruined towers, and seems to have 

 been built with much skill. (See Plate XXXIY.) It is 9 feet in diam- 

 eter on the inside and about 16 feet high. There are three rectangular 

 apartments attached, the walls of which are almost levelled with the 

 ground. In the side of the tower facing the river is a window, about 8 

 feet from the ground and 2 feet high by 1^ wide. I had been previously 

 led to the conclusion that these towers were in all cases built without 

 windows or openings of any kind within reach of the ground from with- 

 out, and it is not improbable that this opening did not communicate 

 with the outside, but served as a door-way between the tower and one 

 of the adjoining apartments. The advantage of such an arrangement 

 in a defensive work, such as we may suppose this to have beeu, is clearly 

 apparent, and evinces not a little intelligence and forethought on the 

 part of the builders. Being built in connection with dwellings and places. 



