Their horses could easily take them out of its reach.
"Maybe they'll stop at the creek," said Ned.

"I should think that the water would hold anything in this thirsty land." Obed shook his head, but offered no further answer.

The thunder of the hoofs now filled their ears, and, as the sound advanced steadily, it was evident that the creek had not stopped the buffalo herd.
The dawn suddenly came up sharp and clear after the manner of southern lands.

The heavens turned blue, and a rosy light suffused the prairie.
Then Ned saw the front of the buffalo herd extending two or three miles to right and to left.

And he saw more.