Complex sentence: The ranges were first explored by white settlers in 1828 by a party headed by Allan Cunningham and Patrick Logan while searching for a route to the Darling Downs from the newly established Moreton Bay penal colony.
Split into simpler sentences: The ranges were first explored by white settlers in 1828. The party was headed by Allan Cunningham and Patrick Logan while searching for a route to the Darling Downs from the newly established Moreton Bay penal colony.