To resume: In spite of the rate at which the buffalo were going, we soon overtook them on our swift mustangs; and now began the most exciting part of our day's sport.  The leading portion of the herd kept close together; but in the rear the animals were separated--some lagging behind, others scattering on either side.  The Indians, with their bows drawn or their spears couched in their hands, dashed in among them, shooting right and left, or plunging their weapons into the shoulders of the brutes--so dexterously aiming the blows, that many of their victims fell pierced to the heart.