APPENDIX SS. 1777 



the southwest that at the distance of 27 miles its mouth, in the San Juan, is hut 2£ 

 miles due east from the La Plata, and ahout 4 miles by the windings of the river. 



On the west bank of the Animas, a short distance below Animas City, are met the 

 high abrupt hills of the Upper Cretaceous series, limiting on the west the great basin or 

 depression in which lie the Florida and Animas in part, and to a greater extent the Los 

 Pinos. Through two lateral spurs, still remaining and extending to the same series 

 on the eastern side, the Animas has cut a gorge where it is so deflected from its former 

 course as to include a width of a mile where the erosion of long ages has left a level 

 area or bench, the intermediate river-bottom being here 600 yards in width. 



From below the second gorge to the mouth of the Florida the terrace formation is 

 characteristic and continuous, with lines more nearly than elsewhere equidistant from 

 the Animas. About 1% miles above the mouth of the Florida was made the following 

 outline, illustrative of the general terrace structure throughout the basin, the distance 

 east to the Florida being about 3£ miles ; at several points, however, the width of the 

 section between the rivers lying in this great depression was considerably in excess 

 of that distance. 



The river was here 250 feet wide and 2 feet deep. The height of the lower mesa above 

 the river varied, being occasionally as low as 25 feet to the south of the Florida, and 

 above varying from 40 to 100 feet ; 60 or 70 feet being at least the average. Its width 

 possessed as great a variation, as had also the immediate bottom. 



Just below the mouth of the Florida, the line of Cretaceous hills on its south extends 

 to the west, and the river here passes through a narrow gorge therein, the walls 

 abrupt, almost vertical on the east, but considerably eroded upon the west. The fol- 

 lowing is an approximate outline at that point : 



1500 ft. 



The encircling high walls of rock about this huge basin, the uniform level nature of 

 these benches within, the drift of pebbly debris covering them everywhere on top and 

 sides, suggest the great inland sea that here existed, portions of whose bottom at pres- 

 ent constitute the divide between the three rivers. With the partial erosion of the 

 confining walls on the south and the outflow therefrom, the subsidence of the waters 

 left the Animas and the Florida distinct streams, and the latter a tributary from its 

 failure to rupture its southern barrier and individually reach the San Juan. With a 

 diminution of its waters and the rapid erosion (comparatively speaking) deepening 

 its outlet through the confining walls to the south, the Avater fell to the height of the 

 lower bench, whence successive and similar operations have depressed it to its present 

 level. 



For over 8 miles from its entrance the river continues in the canon, cut through the 

 huge yellow sandstone cliffs, its passage in general a desolate region, relieved at the 

 distance of 4-£- miles by the successive regression and advance of its walls, leaving 

 spaces of 900 yards or less where grazing occurs. 



The canon at its inception is very narrow, and considerably obstructed by huge 

 blocks of yellow sandstone, fallen from the mass above. It can, however, be passed, 

 and will in time be undoubtedly utilized as a wagon route from the settlements below, 

 which are only reached at present by a long detour via the La Plata. Here the trail 

 leaves the river-bottom and passes the narrow point of the canon over the second 

 bench. Mr. R. L. Smyth, a settler of considerable enterprise, who immigrated with 



112 E 



