Patrick W. Carr said this quote

Once Errol righted himself into some semblance of horsemanship, they set off at an easy canter. That is, the other horses set off at a canter, while Errol's horse settled into a teeth-shattering trot. After a hundred paces he could feel Horace's backbone through the saddle. The other riders pulled ahead without a backward glance, leaving him to his four-footed torture.