Reproduced with the permission of the National Library of Scotland. http://maps.nls.uk/index.html
The White Peak area of the Peak District National Park is punctured with lead mines. Often the small indentations in the earth string out along the landscape as the miners followed the lead veins below.
Many have now been lost on the present day Ordnance Survey OL24 map but thankfully surveyors in the 19th century placed many features on their maps, so looking back can reveal places of interest well worth visiting.