In contact with this, to the westward, was another, stratum of limestone, containing fossil shells of a different character; and still higher up on the stream were parallel strata, consisting of a compact somewhat crystalline limestone, and argillaceous bituminous limestone in thin layers. During the morning, we traveled up the eastern fork of the _Fontaine-qui-bouit_ river, our road being roughened by frequent deep gullies timbered with pine, and halted to noon on a small branch of the stream, timbered principally with the narrow-leaved cottonwood, (_populus angustifolia_,) called by the Canadians _liard amere_. On a hill near by, were two remarkable columns of a grayish-white conglomerate rock, one of which was about twenty feet high, and two feet in diameter. They are surmounted by slabs of a dark ferruginous conglomerate, forming black caps, and adding very much to their columnar effect at a distance. This rock is very destructible by the action of the weather, and the hill, of which they formerly constituted a part, is entirely abraded.
A shaft of the gun-carriage was broken in the afternoon; and we made an early halt, the stream being from twelve to twenty feet wide, with clear water. As usual, the clouds had gathered to a storm over the mountains, and we had a showery evening. At sunset, the thermometer stood at 62°, and our elevation above the sea was. 6,530 feet.
20th.--This morning (as we generally found the mornings under these mountains) was very clear and beautiful, and the air cool and pleasant, with the thermometer at 44°. We continued our march up the stream, along a green sloping bottom; between pine hills on the one hand; and the main Black hills on the other; towards the ridge which separates the waters of the Platte from those of the Arkansas. As we approached the diving ridge, the whole valley was radiant with flowers; blue, yellow, pink, white, scarlet; and purple, vie with each other in splendor. Esparcette was one of the highly characteristic plants, and a bright-looking flower (_gaillardia aristata_) was very frequent; but the most abundant plant along our road today, was _geranium maculatum_, which is the characteristic plant on this portion of the diving grounds. Crossing to the waters of the Platte, fields of blue flax added to the magnificence of this mountain garden; this was occasionally four feet in height, which was a luxuriance of growth that I rarely saw this almost universal plant attain throughout the journey. Continuing down a branch of the Platte, among high and very steep timbered hills, covered with fragments of sock, towards evening we issued from the piny region, and made a late encampment near Poundcake rock, on that fork of the river which we had ascended on the 8th of July. Our animals enjoyed the abundant rushes this evening, as the flies were so bad among the pines that they had been much harassed. A deer was killed here this evening; and again the evening was overcast, and a collection of brilliant red clouds in the west was followed by the customary squall of rain.