Footpath users in the more popular walking areas have contributed to serious erosion problems, particularly on the fragile peat moorlands. The use of some paths by mountain bikers is believed to have exacerbated the problem. Measures to contain the damage include the diversion of the official route of the Pennine Way out of Edale, which now goes via Jacob's Ladder rather than following the Grindsbrook, and surfacing moorland footpaths with expensive natural stone paving. Some rights of way have been damaged by legal and illegal use by off-road vehicles such as 4×4s and trail bikes. Campaigners have sought to reduce their impact. Large-scale limestone quarrying is contentious. Most mineral extraction licences were issued by national government for 90 years in the 1950s and remain legally binding. The park authority has a policy of considering applications for new quarries and licence renewal in the park in terms of the local and national need for the mineral and how unique the source is, in conjunction with the effects on traffic, residents and the environment. Some licences have not been renewed; the RMC Aggregates quarry at Eldon Hill closed in 1999 and landscaped. Proposals from Stancliffe Stone Ltd to re-open dormant gritstone quarries at Stanton Moor in 1999 became a test case, hotly contested by ecological protesters and residents on the grounds that the development would threaten Bronze Age remains at the Nine Ladies Stone Circle, and damage the natural landscape. In 2007, negotiations took place to relocate the development to Dale View quarry in a less sensitive area. The landscapes of the Peak have inspired writers for centuries. Various places have been identified by Ralph Elliott and others as locations in the 14th-century poem "Sir Gawain and the Green Knight"; Lud's Church is thought to be the Green Chapel. Key scenes in Jane Austen's 1813 novel "Pride and Prejudice" are set in the Peak. "Peveril of the Peak" (1823) by Sir Walter Scott is a historical novel set at Peveril Castle, Castleton during the reign of Charles II. William Wordsworth was a frequent visitor to Matlock; the Peak inspired several of his poems, including an 1830 sonnet to Chatsworth House. The village of Morton in Charlotte Brontë's 1847 novel "Jane Eyre" is based on Hathersage, where Brontë stayed in 1845, and Thornfield Hall might have been inspired by nearby North Lees Hall. Snowfield in George Eliot's first novel "Adam Bede" (1859) is believed to be based on Wirksworth, where her uncle managed a mill; Ellastone (as Hayslope) and Ashbourne (as Oakbourne) also feature.