Sea-Ponies
From Equestripedia, the Archives of Equestria!
Sea-Ponies is a book about Seaponies that was written before Sunset Shimmer's fall. As the Hippogriffs didn't become Seaponies until the Storm King's conquests, which is at least a decade after Sunset's descent into slight villainy, it's probable the book was written about another type of Seaponies, perhaps fictional ones.
