Complex sentence: As opposed to a milestone, an hourstone informs travellers that they are a specific number of "hours" away from a particular location, and travellers of the day knew the time designated referred to a fully loaded cart being drawn by a single horse.
Split into simpler sentences: As opposed to a milestone, an hourstone informs travellers that they are a specific number of "hours" away from a particular location. Travellers of the day knew the time designated referred to a fully loaded cart being drawn by a single horse.