DENVER & RIO GRANDE WESTERN ROUTE. 93 
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 XLVII, 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 
granite 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. ; 3 
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 
tbat the higher gravel terrace on the west, as shown in figure 20, is 
