The area is also notable for its quarrying, and Rossendale Flagstone was used widely throughout the country in the 19th century. The flagstones in Trafalgar Square in London were quarried in Rossendale. Upland farming is still carried out, largely of sheep but also of cattle. The history of Rossendale is well documented, largely through the efforts of the historian Chris Aspin, a specialist on the textile industry, and Derek Pilkington, whose efforts led to the preservation of Higher Mill in Helmshore, now Helmshore Mills Textile Museum.