Complex sentence: During Captain Stirling's exploration for a suitable site to establish a colony on the western side of the Australian continent the early 1820's party of boats found a fresh water stream across the river from the site of Guildford which they called Success Hill.
Split into simpler sentences: During Captain Stirling's exploration for a suitable site to establish a colony on the western side of the Australian continent the early 1820's. The exploration party of boats found a fresh water stream across the river from the site of Guildford which they called Success Hill.