We rode on for some distance, the main body keeping together, while scouts were sent forward to look out for buffalo.  At last we reached a broad stream, and were proceeding along the bank, when my companions became greatly interested; and looking out to the left, I saw the whole plain covered with a dense mass of dark objects, which I at once guessed to be buffalo.  It was evident that they were making for the river.  The Indians, urging on their horses, dashed forward to try to intercept the herd before they could cross it.  It seemed to me, however, that we should be too late to do that.