What was the poem in dreamer about racing horse?

The poem in "The Dream" about a racing horse is "The Derby Day" by William Makepeace Thackeray. Here's an excerpt from the poem that mentions the racing horse:

But yesterday a naked moor,

A flat and featureless expanse,

With here and there a rude tomb-stone

Alone to break its dreary trance;

The heath this morn ahip and teem,

With hum of congregated men,

And restless hooves that beat the turf

Like pulse-strokes of a racehorse's mane.