The Earth was flooded for about a year, including the 40 days of rain. Sediments were deposited which were later eroded, metamorphosed and lithified as the waters subsided.
In the evolution narrative the appearance of horses is considered to be recent. Very recent, like, why would an animal evolve which is specifically designed to carry humans if there aren't any humans?
"Many genera of angiosperms became extinct". Their habitat got buried in a world-wide flood. The deposits were subsequently buried so deep that there was no way for the seeds to germinate and reach sunlight.
"Grasslands limited". This is a microcosm of circular reasoning in two words. Whenever the remains of a grassland habitat is found fossilized it's assigned to something other than the Eocene.
"Subtropical climates with heavy rainfall supported distinctive forests in northern and southern latitudes." This is another example of the circular reasoning which lies at the very heart of the geological timescale.
If we (that's me and the Holy spirit) use deductive reasoning in how we account for the evidence, a buried ecosystem, we come to the conclusion that the Eocene was deposited in a world-wide flood.