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Show 276 Lewis awl Clarke's E~t:pcditi o11 small rapid on the north side, from which it grad uall,r widens to one thousand four lmndred yards. ami a t the d i -: ~ tance of five humh·ed aml forty~eight pole ~ rcaehcs the head ofthe rapids, narrowing as it approaches them. Here tl~t• hills on the north which had withdrawn fr·om the bank closely border the river, which, for the space of three hundred and twenty poles, makes its way over the rocks with a descent of thirty feet: in this course the c ut-rent is contracted to five hundred and eighty yards, and a fter thro·wing itself over a small pitch of five feet, forms a beautiful cascade of twenty-six feet five inches; this does not however fall immediately perpendicular, being stOilped by a part of the rock which projects at about one third of the distancr. After descending this fall, and passing the cottonwood island on which the eag·Jc bas fixed its nest, the 1•ivcr goes on for five hundred and thit·ty-two poles over rapids and little falls, the estimated descent of which is thirteen feet six inches till it is joined by a large fountain boiling up underneath the rocks ncar the edge of the river. into which it falls with a cascade of eight feet. It is of the most perfect clearness and rather of a bluish cast: ami even after fall ing into the Missouri it preserves its colour fol' half a mile. From. this fountain the rh·cr descends wHh inct·cased rapi~ dity for the distance of two hundred and fout·tecn 11olcs, dn~ ring which the estimated descent is five feet: from this fot• a distance of one hundred and thirty-five poles, the rin .r descends fo~rteen feet seven inches including a pcr·pcndicular fa1l of six feet seven inches. The river lms now become pressed into a space of four hundred and seventy-three yar.ds, and here forms a grand cataract by faHing over a plam rock the whole distance across the river to the dept.h of. forty:seven feet eigh't inches: after recovering itself the Mtssourt then proceeds with. an estimated descent of tluce feet, till at the distance of one hundred and two poles it again is precipitated down the Crooked falls of nineteen f6et perpendicular; below this at the mouth of a dee'{l ra- Vp the .lUtssom·i. 277 l'ine is a fall of five feet, after which for the t.listance or nine hundred and seventy poles the descent is much more gradual, not being mol'e than ten feet, and then succeeds a handsome leYel }>lain for the space of one hundred and seventy~eight poles with a computed descent of three feet, making a Lend towards the norf h. Thence it descends during four huudt·ed and cigl1ty poles, about eighteen feet and a half, when it makes a pcrpcndiculal· fall of two feet , which is ninety poles beyond the great cataract, in ap· proaching which it descends thirteen feet within two hundred yar<ls, and gathel'ing streng th from its confined channel, which is only two hundred and eighty yards wide, l'ushes over the fall to the depth of eighty-seven f eet an'l three quarten of an inch. After raging among the rocks and losing itself in foam, it is compressed immediately into a oed of ninety-three ·yards in width: it eontinues for three hundred and forty poles to the e ntrance of a run or deep ra· vine where there is a fall of thrre feet, which. joined to the decline of the river· during that course, makes the descent six feet. As it goes on the descent within the nex t two hundred and forty poles is only four feet: from t his passing a run or deep ravine the descent for fout· hundred poles is thjr·teen feet; within two hundl'ed and forty poles a second de! Scent or eighteen feet; thence one hundred and sixty poles a llescent of six feet; aftet• which to the mouth or llox·tag(~ creek, a distance or two hundred and eighty poles, the descent is ten feet. }.. ... rom this survey and estimate it results that the rh·er experiences a descent of three hundred and flfty-two feet in the course of two and three quartet· mile~)' from the commencement of the ra1lids to the mouth of Portage cx~eek, exclusive of the almost impassable rapids which extend for a mile below its entt·ance. 'I'he latitude of our camp below the entrance of Portage creek, was found to be 47° 7' 10" s, as deduced from a meridian altitude of the sun's lowe~• limb taken with octan t by back 9'bi~l·vatiou giving 53° 1 O'. |