The geology at Wairdlaw (which seems to translate from old Scottish to mean 'Marsh Hill') has meant it was an active mining site for over a century. First, mining of the local quartz-dolerite intrusions common to the Bathgate Hills, and then mining a limestone outcrop, which tends to occurs within the lava rocks of this area. The same durable quartz-dolerite found here is what makes up 'The Knock' (one of the highest points in West Lothian) nearby to the south.
Geological Map of Bathgate Hills
The lime quarry here was the latter of the two quarrying industries at this site, and one of several lime quarries within just a mile radius. Lime had always been used in building, for mortar, harling (roughcast) and plaster. However, from the eighteenth century, much larger amounts of lime were sought for improvements to farmland. By adding burnt and powdered lime to the soil, crop yield could be greatly increased.
The quarry at Wairdlaw took the form of a narrowish rift cut in the hill, running roughly north/south and is not accessible today, being fenced off. However there is a picture of it below.
Wairdlaw Quarry
The lime kilns for the former quarry are still largely intact. They comprise two draw kilns, with barrel-vaulted access tunnel; built of whinstone with sandstone dressings, 50ft long and 27ft high. They can still be seen through the woodlands that have been added in the last few years near gz, on the other side of the fence. The picture below shows what they looked like before all the recent woodlands.
Wairdlaw Limekilns
It's a muddy route to gz so good boots/wellies are advisable. Two Parking waypoints have been added, from the east and the west. The east one is probably most convenient if just doing this cache alone. There is a Bookmark List for this series of caches in The Bathgate Hills, here.