Bonnie Prince Fetlar by Marshall Saunders — Read

"The evening is young yet. Dad says you are a racing pony. Come, show me your paces," and in a jiffy this swift girl had Drunkard chained to a veranda post, and had seized a new riding bridle that someone had thrown on a chair.

Then she sprang on my back, and giving my neck a slap said, "Head of the Lake, racer."