102 GUIDEBOOK OF THE WESTERN UNITED STATES. 
From Sappington a branch line continues up the south side of the 
river for a mile or so and then turns up Antelope Creek to Norris and 
Pony. A short distance beyond the station the 
Northern Pacific crosses the St. Paul line, and from 
this point on through the canyon the Northern 
Pacific is on the north side of the river. About 2 
miles above Sappington the river again cuts through a ridge of the 
hard rocks which project from the great mass on the left. In this 
canyon the formations composing the earth’s crust have been greatly 
Sappington. 
Elevation 4,205 feet. 
St. Paul 1,076 miles. 
disturbed and tilted up on edge, but it is not easy to understand just — 
how the originally horizontal beds of limestone and quartzite were 
forced into their present positions.? Here again the stream has cut 
a canyon across a spur of hard rock projecting from the left, and here, 
as below Sappington, the stream could have avoided the obstruction 
by keeping on the soft rocks farther north. 
Beyond this canyon the river flows through an open valley com- 
posed of Jurassic and Cretaceous rocks which the traveler will hardly 
aoe 1 
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d near Lime Spur, Mont., as seen from the Northern Pacific 
ailway, looking west. 
be able to distinguish from the train. At milepost 26 he enters the 
deepest and most picturesque canyon on this part of the line. The 
rocks in this canyon are in the form of a great anticline, as shown 
in figure 20, but the fold is so large and so badly broken that 
FIGuRE 20.—Section of great anticlinal fol 
R 
its form is difficult to determine. 
looking west, with the limestone ridge 
AB projecting into it from the left. When 
tha +] + £41, 7 
Fe eS 
SAA SU LOR 
beds, on a surface represented by DEF 
which was smooth and with no irregulari- 
ral 
hange 
occurred, such as an elevation of the land 
or an increase in the volume of water, 
pee NR, Y gine, 1 ; = ee 1t Pe 
greater cutting power, and it began to 
This fold has been produced by 
trench the soft material over which it 
flowed. As it cut deeper it came into 
contact with the limestone, but the 
stream was intrenched in its course and 
80 maintained its position, cutting its 
way down to G, its present level. 
The soft rocks upon which Jefferson 
River assumed its present course are the 
Tertiary lake beds, which probably filled 
the valley to a depth of several hundred 
feet. 
*The peculiar relations of the several 
formations, as seen in the small canyon 
* 
