The river falls in cataracts and rapids over Boo ft.
On some of these channels deep gorges were eroded heading in temporary cataracts which exceeded Niagara in height but not in breadth; the pools excavated by the plunging waters at the head of the gorges are now occupied by little lakes.
Between the mouths of the Hartebeest and Molopo, in 28° 35' S., 20° 20' E., are the great waterfalls of the Orange, where in a series of cataracts and cascades the river drops 400 ft.
But just before reaching the Uaupes there is a long series of reefs, over which it violently flows in cataracts, rapids and whirlpools.
Evans, " The Rocks of the Cataracts of the River Madeira and the adjoining Portions of the Beni and Mamore," Quart.