248 Geology and Botany of Northern Pacific Railroad. 



much like that of the Drachenfels, at the head of Belt Creek ; 

 and third, a rhyolite, on the summit of Little Belt Mountain. 



At Neihart, the centre of the Archaean nucleus of the Little 

 Belt Mountains is reached. The prevailing granite is reddish 

 and somewhat banded with brown and green, and though very 

 massive is indistinctly bedded and apparently metamorphic. It 

 is cut by enormous dykes of a very coarse and mottled granite, 

 consisting of obscurely rounded masses of feldspar separated by 

 hornblende and black mica. These granite rocks are traversed 

 by a great number of fissure-veius, generally with vein stones of 

 quartz, heavy spar, and oxide of manganese, and carrying sul- 

 phides of silver and lead ; the ores are rich but the veins small. 



On the south side of the valley at Neihart the cliffs of granite, 

 1200 feet in height, are covered with a sheet of Potsdam sand- 

 stone several hundred feet in thickness, the contact being visible 

 for miles. The sandstone is red, generally soft, but sometimes 

 a coarse and hard conglomerate. It here contains no fossils, but 

 is full of annelid borings (Scolithus), and has the aspect — as it 

 has the geological relations — of the Potsdam in the Black Hills 

 and in the Adirondacks. On the summit of the mountain, some 

 of the upper beds of sandstone are filled with, and largely com- 

 posed of, primordial trilobites. 



The evidences of former glacial action in the Belt Mountains 

 are abundant but are not of a striking character. They con- 

 sist of beds of boulder clay, and in some of the higher val- 

 leys, of roches moutonnees or smoothly planed surfaces. Gla- 

 cial striae were not observed, having been obliterated by wea- 

 thering. * 



All the upper portion of the Belt Mountains is covered with a 

 dense forest composed of Douglas's and Engelmann's spruces, 

 Abies Douglasii, and A. Engelmanni, the balsam fir, Abies 

 concolor, and Pinus contorta. In places, the trees are heavily 

 draped with tufts and streamers of the jet-black fibres of Alec- 

 toria sarmentosa ; while many trees and particularly dry 

 branches are decorated with bunches of the lemon-yellow Ever- 

 nia vulpina. Lower down on the mountain are scattered trees 

 of Pinus ponderosa. 



The valley of Smith's River separates the Great Belt from the 

 Little Belt Mountains. It is as picturesque and beautiful as the 



