Horses slump.

March 17.

Snow going off very gradually under the sun alone. Going begins to be bad; horses slump; hard turning out. 

See where the cattle, which have stepped a few inches one side the sled-track, have slumped two feet or more, leaving great holes.

H. D. Thoreau, Journal, March 17, 1856

Going begins to be bad; horses slump; hard turning out. See March 5, 1856 ("It is very hard turning out, there is so much snow in the road. Your horse springs and flounders in it.”); March 30, 1856 (“[T]he Corner road is impassable to horses, because of their slumping in the old snow”).. Compare February 9, 1855 (“The snow is so light and dry that it rises like spray or foam before the legs of the horses. They dash it before them upward like water. It is a handsome sight, a span of horses at a little distance dashing through it, like suds around their legs. ”)