Evidence of early neolithic salt pans, dating to 3766-3647 BCE, have been unearthed in Yorkshire. Evidence of bronze age production, circa 1,400 BCE, has been identified in Somerset. Iron age production in Hampshire. Roman Rock Salt production production in Cheshire. Salt was produced from both mines and sea in Medieval England. The open-pan salt making method was used along the Lincolnshire coast and in the saltmarshes of Bitterne Manor on the banks of the River Itchen in Hampshire where salt production was a notable industry.