1/4 horse:
a horse of a small, stocky breed noted for agility and speed over short distances. It is reputed to be the fastest breed of horse over distances of a quarter of a mile
Mustang:an American feral horse, typically small and lightly built.

If it wasn't fast Mike, you are again correct, but I wouldn't tell Barb.
Hope to see you both in Eureka Springs for the CAA!