DENVER & RIO GRANDE WESTERN ROUTE. OS 



normal stage. The traveler may be interested in the circular holes, 

 ranging in diameter from a few inches to many feet, that have been 

 carved in these boulders, and he may wonder how they have been 

 made. Some of these " potholes," as they are called, are shown in 

 Plate XL VII, B (p. 98). If he could look down into the potholes he 

 might see the " tools " by which they were carved. These tools are 

 small boulders, which the water, when it is high, whirls round and 

 round in the narrow space. This constant grinding wears the holes 

 deeper and broader and unites many adjacent holes, forming a chan- 

 nel in the rock. 



About three-quarters of a mile beyond milepost 224, which is in 

 the narrowest part of the gorge, the railroad crosses a rather large 

 creek that enters the river from the east. A branch road once ran 

 up this stream nearly 6 miles to some iron mines, but the mines 

 were unsuccessful and the line has been discontinued, although it 

 is still shown on some recent maps. The point where this branch 

 joined the main line was known as Hecla Junction. The canyon 

 is near the western edge of the granite area, but the gravel filling 

 on the left can not be seen from the train. 



About half a mile beyond milepost 230 the railroad crosses the 

 river and in a short distance emerges from the rocky reaches of 

 Brown Canyon. This canyon is extremely interesting from many 

 points of view. To the geologist it reveals a whole chapter in the 

 history of this region, a chapter that tells of its depression down 

 nearly to sea level, when the highest mountains of Colorado were 

 small ridges only 4,000 or 5,000 feet in height, and then of its eleva- 

 tion to its present position. To the lover of beautiful scenery it 

 affords a pleasing variety of landscape, for one tires of even the 

 finest scenery if it is without variety; but in passing from the open 

 valley above Salida, where the principal objects in sight are the 

 great mountain peaks of the Sawatch Range, to the confining granite 

 walls of Brown Canyon the traveler experiences a pleasing sensa- 

 tion of the nearness of the landscape and of being brought face to 

 face with the works of Nature. To the artist the canyon is beau- 

 tiful because of its ruggedness and of the many vistas that may 

 be obtained of the stream boiling and foaming through some narrow 

 part, or of some beautiful side ravine where the dull gray of the 

 gi'anite is enlivened by the deep green of the conifers and the soft 

 foliage of the aspens, or, if the season is autumn, by the gleam 

 of gold which the yellow leaves give to the landscape. 



The general aspect of the canyon, as well as its relation to the 

 gravel filling on the west, may be seen to excellent advantage by 

 looking back from the train after it has cleared the granite walls 

 and crossed the river to the west side. Here the traveler can see 

 that the higher gravel terrace on the west, as shown in figure 20, is 



