GMS today is an amalgamation of 4-5 distinct quarries into one large complex. The southern series are the oldest, starting from the mid 18thC as three distinct firestone quarries, what we see today as Sawmills, Roman Road and Jones. In the early to mid 19thC it was quarried in much further and on a larger post industrial age scale opening up Road Quarry and the Main Series itself.

Firestone was quarried partly as a building stone and also for use in furnaces as it stands high-heat very well. The stone has no grain, it can be cut in any direction and is termed a free-stone. Before the industrial revolution and the coming of the railways this was the best stone to be had in the southeast without significant transport problems; cost! Once better stone could be brought from further away more easily and cheaply the demand for firestone faded.

Old plate rails from the Croydon, Merstham and Godstone tram road (1805-c1830) have been relaid within the quarry for haulage making this one of the few underground sites remaining in the UK with in situ plateways. As the firestone quarrying declined in the latter half of the 19thC it was superseded in part by hearthstone mining, a reworking of the inferior beds and firestone waste with a different use: step whitening blocks!

From around 1890 until WW1 the site was used by French mushroom growers who left their mark. Many of these seem to have left during the war; graffiti in a neighbouring quarry suggests that some did not come back. There is some suggestion that the War Dept considered the site for explosive storage during WW1. After the war there was another attempt at growing mushrooms but this was not successful. The site was considered as a shelter during WW2 but not officially used, although it is known that local people used to shelter in the ‘caves’.

At various times since WW2 the site has been accessible by casual visitors who have left their mark and at other times it has been sealed. Today the site is gated and looked after by the Wealden Cave & Mine Society (WCMS). The site is also used by hibernating bats and access is restricted in winter time with close liaison with the local bat group. Visits can be arranged by WCMS during summertime for groups with a genuine interest in these old workings. many others with all aspects of exploration and archaeology discussed in full.