Complex sentence: All of the boulders in the flows are remnants of quartzites that were repeatedly ground down as a consequence of repeated cycles of freezing and thawing; they are found principally in the Port Stanley Beds and to a lesser degree in the Port Stephens Formation.
Split into simpler sentences: All of the boulders in the flows are remnants of quartzites that were repeatedly ground down as a consequence of repeated cycles of freezing and thawing. They are found principally in the Port Stanley Beds and to a lesser degree in the Port Stephens Formation.