FROM FORT BENTON TO LATITUDE 49° 30’. 545 
circle formed by the mountains, stretching from the gate of the mountain on the Missouri to the 
sources of Sun river, stands a lofty, conical shaped mountain, called by the Indians Hart 
mountain; it is ten miles from the main chain of mountains, and is a very prominent land- 
mark, indicating the position of Lewis and Clark’s Pass, and another pass on the south fork of 
Sun river. 
Night clear and cool. In the afternoon passed a large fork coming in on the south; it is nearly 
as large as the main stream, and does not appear to have an extensive valley in the mountains. 
Just above this I killed a large elk, and therefore I call this ‘Elk fork.” The country continues to 
grow more broken, and the soil richer. Collected several new specimens of flowers, but no birds 
or reptiles. Encamped early, having made 23.45 miles. 
May 17.—Moved early, and leaving the river on our left, struck for a towering snow-capped 
peak, which appears to mark the spot where the river comes out of the mountains. 
The face of the country clearly indicates our approach to a great mountain range. Huge 
fragments of granite, limestone, sandstone, and a few granite boulders, are scattered over the 
plain. Noticed outcroppings of strata of sandstone and limestone, with a nearly vertical dip, 
running north and south. In fourteen miles came to scattering scrub-pines, being again near 
the river, and in one mile more extend to a lovely valley some two miles in breadth, and extend- 
ing up the river three or four miles. This valley is elevated above the river some two hundred 
feet. The soil is a rich gravelly loam, grass luxuriant, and a profusion of gay colored flowers. 
Near the upper end of the valley are two small lakes, in which numbers of water-fowl were 
swimming. Pushed on as far as it was practicable to take the odometer wagon, and encamped 
on the edge of the river in a narrow bottom, fringed with a few pines and red birch. 
May 18.—To-day I remain in camp to determine the latitudes, examine the mountains for a 
pass, and to collect specimens. Sfarted early up the river on foot; valley narrows, bottoms dis- 
appear, and the river is shut in by precipitous mountains. Climbing along the side-hill over 
masses of rock fallen from the precipices above, came to a narrow strip of level ground along the 
stream, and following it, in eighty rods reached a perpendicular wall of limestone rock one hun- 
dred feet high, in which is an opening twenty feet wide, and extending from top to bottom, and 
through this the river flows in a swift, deep current. Ihave named this the Gate of Sun river. 
The sources of Sun river are evidently far up in the mountains, and, being very anxious to make 
further explorations, I attempted to climb the rocks on the right bank, but did not succeed. I 
then ascended one of the peaks next below the highest, which it was impossible to ascend; and 
the view from this point was magnificent. Above and around were snow-covered hills and the 
breath of winter, while the luxuriant grass and gay flowers in the valley far below were fast 
approaching maturity under the summer’s sun. Collected twenty new varieties of flowers and a 
few geological specimens; returned to camp, and took a meridian altitude of the sun, which 
gives for the latitude of this camp 47° 32! 39”, which agrees very well with the position as given 
by the compass and odometer line. There is no timber here suitable for building purposes; the 
pine is small and scrubby, and is only fit, perhaps, for railroad ties. The soil is excellent; but 
there is not a sufficient extent of level land to render it a good location for farms. 
May 19.—Morning clear and warm; made a late start. Our course lay close along the mount- 
ains, over hills of considerable elevation, covered with scrub-pines twenty to thirty feet high, 
through which we had much difficulty in taking the odometer wagon. In fact, this delays us 
every day, and renders a long march impossible; but, being anxious for a correct measurement 
of the distance to the boundary, I shall take the odometer through. The mountains now trend to 
the east of north, but appear to terminate that course at a conical peak distant about twenty-five 
miles. In four miles came to a small spring-brook, which is the most southerly headwaters of 
the Teton river, and in ten miles more reached two beautiful creeks, which unite just below our 
crossing and flow through a deep valley towards the Teton. Passed over many steep hills, and 
the country to-day is more hilly, and travelling more difficult than on any previous day. Soil 
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