148 GUIDEBOOK OF THE WESTERN UNITED STATES. 
The railway, from the point where it crosses Clark Fork to Trout 
Creek, follows the outcrop of the Ravalli formation, which dips to 
the left; and it is probable that the hills on the left are composed of 
the next higher formation, the Newland limestone, but they are so 
far distant and so nearly covered with trees that it is doubtful if the 
traveler will be able to distinguish formations. 
Just beyond milepost 50 the train crosses Big Beaver Creek, a 
large stream joining the river from the south, and a little farther on 
Vermilion Creek enters from the other side. The valley of the 
Vermilion is particularly interesting, for at its mouth there is a 
marked delta, visible from the train on the high line, which is 320 
feet above the present river level. This delta could have been built 
outlet, else more material would have been brought down, possibly 
enough to completely fill the valley of Clark Fork. 
At Trout Creek the hills on the south are composed of the Newland 
limestone, which dips toward the river at an angle of 40°. It is 
probable that this is the same belt of limestone as 
sevet Greek, that which was seen on the left at a point just below - 
St Paullgraie, Thompson Falls, and it is undoubtedly the same as 
the limestone which occurs on the south side of the 
valley as far as Noxon. 
A short distance beyond Trout Creek the river makes a decided 
bend to the left and swings against the bluffs on that side. The 
railway follows the river and at milepost 59 is close to the mountain 
side, which is nearly bare, having been swept clean of trees in the 
great forest fires of 1910. On one of these smooth slopes horizontal 
beach lines are visible. They can be identified up the slopes to a. 
height of 1,200 feet above the river, or 3,500 feet above sea level, but 
beyond that height no trace of such markings has been found. The 
