The journal tells the rest of the story:-- "At the extremity of this basin stood a high black rock, which, rising perpendicularly from the right shore, seemed to run wholly across the river: so totally, indeed, did it appear to stop the passage, that we could not see where the water escaped, except that the current was seemingly drawn with more than usual velocity to the left of the rock, where was heard a great roaring.

We landed at the huts of the Indians, who went with us to the top of the rock, from which we had a view of all the difficulties of the channel.

We were now no longer at a loss to account for the rising of the river at the falls; for this tremendous rock was seen stretching across the river, to meet the high hills on the left shore, leaving a channel of only forty-five yards wide, through which the whole body of the Columbia pressed its way.

The water, thus forced into so narrow a passage, was thrown into whirls, and swelled and boiled in every part with the wildest agitation.

But the alternative of carrying the boats over this high rock was almost impossible in our present situation; and as the chief danger seemed to be, not from any obstructions in the channel, but from the great waves and whirlpools, we resolved to attempt the passage, in the hope of being able, by dexterous steering, to descend in safety.