Complex sentence: Also the corresponding lack of Celtic derived place names in West Sussex, the names are all Saxon, except for the Arun and Chithurst; perhaps Cissbury from Sidh, compare Sidown in Hampshire.
Split into simpler sentences: Also the corresponding lack of Celtic derived place names in West Sussex. The names are all Saxon, except for the Arun and Chithurst; perhaps Cissbury from Sidh, compare Sidown in Hampshire.