"bea[u]ty and magnifficence"
"I had scarcely infixed my eyes from this pleasing object," wrote Lewis—referring to the "handsom fall,"
before I discovered another fall above at the distance of half a mile; thus invited I did not once think of returning but hurried thither to amuse myself with this newly discovered object. I found this to be a cascade of about 14 feet possessing a perpendicular pitch of about 6 feet. this was tolerably regular stretching across the river from bank to bank where it was about a quarter of a mile wide; in any other neighbourhood but this, such a cascade would probably be extoled for it's beaty and magnifficence, but here I passed it by with but little attention, determining as I had proceded so far to continue my rout to the head of the rappids if it should detain me all night.
During his survey of the falls on June 19, Clark calculated the south end of this "pleasing object" was "N 86° W. 135 poles," or 2,227 feet upstream from the "2d great falls," or "handsom falls." Sometime in the 1880s Paris Gibson, the founder of the city of Great Falls, named it for John Colter, who was a member of Clark's survey party.1
This photo probably was taken in late 1908. To gain a sense of the scale of this waterfall, find the six workmen at right of center (pass the cursor over the image). They are building a shear dam to divert the river away from the north side of the channel so that work can begin on the intake, power house, and tailrace for the Rainbow Dam. Since 1910, when the dam was completed, Colter's Falls have been hidden from view beneath the reservoir's surface.
1. Paris Gibson, "The Falls of the Missouri: Their Past, Present and Future," Rocky Mountain Magazine, Vol. 1, No. 1 (September 1900).