78 GEOLOGICAL SUEVEY OF THE TERRITOEIES. 



limestone on the west side of the river is a considerable thickness of 

 the rusty-brown sandstones, pudding-stones, clays, &c., that charac- 

 terize the Silurian near the Three Forks ,• but these beds are thiuniug 

 out very rapidly in their southward extension. Spanish Creek flows 

 into the Gallatin from the divide on the west side, and nearly separates 

 the unchanged strata above from the gneissic rock below. A tew patches 

 of limestones occur here and there. In the limestones on the east side 

 of the Gallatin, great quantities of fossils occur, Froductus semireUculaftis, 

 P. longispimtSj Strophomena analoga, Hemipronetes crenistria, and many 

 others (see catalogue of Mr. Meek) of Carboniferous age. On the west 

 side of the river thelimestone-ridgessoon disappear and the massive gran- 

 itoid rocks appear, rising to an enormous height, covered with great quan- 

 tities of huge fragments. On theeast side, the Carboniferous and Silurian 

 beds extend up for about live miles, when they slowly disappear over the 

 summits of the granitic mountains. At first the Carboniferous lime- 

 stones extend down to the water's edge, but in ascending the river the 

 strata rise rapidly until the entire mass is exposed, resting upon the 

 granitic group. Although there is no positive non-conformity between 

 the Carboniferous and Silurian, yet there appears to be a well-defined 

 physical line of separation. The Silurian limes^tones are more massive, 

 brittle, cherty, and hkve an ancient look, while the Carboniferous beds 

 are more pure limestone, and with thin, well-defined layers. These 

 upper limestones also have a more modern appearance. The sides of 

 the mountains on both sides of the Gallatin, from crest to crest, are 

 wonderfully rugged and picturesque. The limestones are frequently 

 weathered into the most peculiar columns, while the granites are worn 

 into grand, castellated forms. The crest of the ranges on the entire 

 divide on the east side is composed of volcanic rock, while on the west 

 side the central mass is granitic, rising in high, sharp peaks, 10,000 to 

 10,500 feet above the sea. The pines cover the sides of the mountains 

 quite thickly in many places, sending their roots among the rocks 

 where the descent is almost vertical. About ten miles above the 

 entrance of the canon the granitic rocks rise to the surface on the east 

 side of the Gallatin, and extend ten miles up the river in full force on 

 both sides, rising quickly to a height of 2,000 to 2,500 feet above the 

 bed of the river. At first, detached beds of limestone may be seen upon 

 the high granite-walls, as they disappear upon the summits of the 

 mountains. The little streams, as they flow down from the divides on 

 either side, have cut fearful gorges through the granites. The narrow 

 valley on both sides of the river is covered with immense rounded 

 granite-bowlders, rendering the traveling very difficult. For a dis- 

 tance of ten miles we were obliged to travel with our pack-train very 

 slowly and with great risk. In no part of the West have we found a 

 more difQcult trail, and this may account for the fact that so few per- 

 sons have ascended the stream. As we crossed one of the little streams 

 that flow into the Gallatin from the west side, we observed that the 

 water was very muddy. Mr. Sloane, a prospecter, who accompanied 

 us for protection while he was searching for mines, suspecting that 

 somewhere near the head of the stream a fellow- miner had found a good 

 thing and was working it out, quietly followed the stream up to its 

 source. He found near the head that a few days before lightning had 

 struck the ground, plowing it up in long lines sometimes 100 yards 

 or more and six feet in depth. The pines grew very thickly, but over 

 an area 150 feet wide and about 600 yards long the trees were torn 

 down and broken in pieces. Trees two and a half feet in diameter were 

 broken off and were thrown several hundred yards down the stream. 



