Complex sentence: Their fieldwork uncovered a large amount of Roman and medieval domestic waste and, most importantly, a large amount of worked Mesolithic flints, raising the possibility that the site might have been a stopping point for hunter-gatherers.
Split into simpler sentences: Their fieldwork uncovered a large amount of Roman and medieval domestic waste and, most importantly, a large amount of worked Mesolithic flints. It is believed that this would have been a stopping point for hunter-gatherers.