Wheelhorse

The off wheel-horſe a grey, named Single Peeper, ſold for 50 [guineas] […] The near wheel-horſe cheſnut, named Chance.

Source: wiktionary

The driver […] neither knew any thing, said any thing, or did any thing but watch a dozen equine ears, and keep six reins taut in his hands, and coax the off wheel[-]horse with the belly of his whip-lash every two minutes, invariably accompanying the stroke with a tremendous solitary cluck.

Source: wiktionary

“Ay! he med well say that,” repeated the wagoner, still digesting the pleasure of Ben Lee’s compliment, and slapping the wheel[-]horse’s vast flank, so that the fairy chime began again, and the smack resounded like an accompaniment to its music.

Source: wiktionary

In contrast to the methods used in New England all the lumber from the high Sierras is taken out in the summer instead of the winter. Teams of about seven pairs of horses, or mules, or traction engines, are used. Teams draw two or three wagons, and are managed by one driver who rides on a wheelhorse and guides with one rein, whip and voice.

Source: wiktionary