DENVER & RIO GRANDE WESTERN ROUTE. 75 
West of the outcrop of the Morrison lies a red sandstone that is in 
places at least a thousand feet thick, This sandstone is particularly 
prominent about Manitou, in the valley of Fountain Creek, and for 
this reason is called the Fountain formation. This sandstone is of 
middle Carboniferous (Pennsylvanian) age. A limestone or gray 
and pink dolomite ** about 100 feet thick and a sandstone of about 
the same thickness lie below the Fountain formation. This sand- 
stone rests on the granite of the Front Range. All the rocks below 
the Dakota sandstone are prevailingly red, and this color is well dis- 
played in the valley west of the hogback. 
At Burnito siding may be seen some of the canals that carry water 
to irrigate the valley below, as well as the pipe line which supplies ° 
Canon City with water. The pipe line is high up on the north 
(right), and the water is carried by gravity into a settling reservoir, 
which may be seen on a hill to the right. Below the city aqueduct 
is a canal, which is taken by a tunnel through the hogback to irri- 
gate the orchards on the north side of the valley. On the south there 
are two canals, one high up on the hillside and one near the level 
of the river bottom. The higher canal receives its water from Grape 
Creek, which enters the river just at the edge of the mountain; the 
lower one takes water from Arkansas River near the mouth of this 
creek, 
A short distance above Burnito siding the traveler is face to face 
with the imposing portal of the Royal Gorge. (See Pl. XXXITI, 
B.) On the left is the old Hot Springs Hotel, now abandoned, and 
on the right and considerably above the railroad are some small tun- 
nels through which the city pipe line is carried. The passage seems 
almost barred by the great slab of gneiss which projects from the 
north and stands 400 or 500 feet high. The traveler may imagine 
that the train will at once plunge into the shadowy depths of the 
mighty gorge, but after passing the portal he finds that the canyon, 
though rocky, is not particularly rugged or precipitous. 
The observant traveler will soon notice that there is close connec- 
tion between the character of the rock and the shape and narrow- 
hess of the gorge. Where the rock is massive granite cut by few 
jomt planes the gorge is narrow, but where the rock is intricately 
banded and composed of many layers of diverse appearing rocks it 
1S wider and the slopes are more gentle. The differences in the form 
and width of the canyon are due to differences in the resistance which 
the various kinds of rock have offered to the cutting power of the 
stream and to the processes of weathering. ~ 
Berane aN aa 
 ™A dolomite is generally regarded | lime and magnesia, containing 55 to 65 
"Sa limestone, but a limestone con- | per cent of carbonate of lime and 35 
sete essentially of carbonate of lime, | to 45 per cent of carbonate of mag- 
and a dolomite of double carbonate of | nesia. 
/ 
