This road he concluded to take, and therefore sent back Drewyer to the forks with a second letter to captain Clarke apprising him of the change, and then proceeded on.  The valley of the west fork through which he now passed, bears a little to the north of west, and is confined within the space of about a mile in width, by rough mountains and steep cliffs of rock.  At the distance of four and a half miles it opens into a beautiful and extensive plain about ten miles long and five or six in width:  this is surrounded on all sides by higher rolling or waving country, intersected by several little rivulets from the mountains, each bordered by its wide meadows.  The whole prospect is bounded by these mountains, which nearly surround it, so as to form a beautiful cove about sixteen or eighteen miles in diameter.  On entering this cove the river bends to the northwest, and bathes the foot of the hills to the right.  At this place they halted for the night on the right side of the river, and having lighted a fire of dry willow brush, the only fuel which the country affords, supped on a deer.  They had travelled to-day thirty miles by estimate:  that is ten to the Rattlesnake cliff, fifteen to the forks of Jefferson river, and five to their encampment.  In this cove some parts of the low grounds are tolerably fertile, but much the greater proportion is covered with prickly pear, sedge, twisted grass, the pulpy-leafed thorn, southern-wood, and wild sage, and like the uplands have a very inferior soil.  These last have little more than the prickly pear and the twisted or bearded grass, nor are there in the whole cove more than three or four cottonwood trees, and those are small.  At the apparent extremity of the bottom above, and about ten miles to the westward, are two perpendicular cliffs rising to a considerable height on each side of the river, and at this distance seem like a gate.  In the meantime we proceeded at sunrise, and found the river not so rapid as yesterday, though more narrow and still very crooked, and so shallow that we were obliged to drag the canoes over many ripples in the course of the day.  At six and a half miles we had passed eight bends on the north, and two small bayous on the left, and came to what the Indians call the Beaver’s-head, a steep rocky cliff about one hundred and fifty feet high, near the right side of the river.  Opposite to this at three hundred yards from the water is a low cliff about fifty feet in height, which forms the extremity of a spur of the mountain about four miles distant on the left.  At four o’clock we were overtaken by a heavy shower of rain, attended with thunder, lightning and hail.  The party were defended from the hail by covering themselves with willow bushes, but they got completely wet, and in this situation, as soon as the rain ceased, continued till we encamped.  This we did at a low bluff on the left, after passing in the course of six and a half miles, four islands and eighteen bends on the right, and a low bluff and several bayous on the same side.  We had now come thirteen miles, yet were only four on our route towards the mountains.  The game seems to be declining, for our hunters procured only a single deer, though we found another for us that had been killed three days before by one of the hunters during an excursion, and left for us on the river.