 The water above the Black canon had been shoal, and the current swift.Rapids had occurred in such quick succession as to make navigation almost impossible, and there would be no object in proceeding beyond the Great Bend.The difficulties encountered in the canon were of a character to prevent a steamboat from attempting to traverse it at low water, and we had seen drift-wood lodged in clefts fifty feet above the river, betokening a condition of things during the summer freshet that would render navigation more hazardous at that season than now.