How Old Are Merstham Mines?

Martin Hatton

Although there are documents dating from medieval times which refer to Surrey Upper Greensand quarries1 there has until recently been little firm evidence for dates earlier than that.

The fact that mining techniques appear to have changed little over time makes dating an even greater problem. A similar problem exists with Roman-British and later iron workings in the Weald and elsewhere. In response to this difficultly a guide to archaeological field work (OS, 1963, p95) states that 'definite evidence in the form of pottery &C.' is (therefore) required before a site can be accepted as Roman.

Unfortunately the only pottery older than Victorian era, which has come from the mines, was a jug from Bedlams bank (Hatton, 1977, p15-17). As that was only mid 16th century it still does not help in the desire to prove an early date for at least some of the quarries.

An alternative approach is to consider the date of the buildings for which the stone was used. This is not a perfect method since the stone could be much older than the building: it might have been quarried for an earlier building which was subsequently demolished and the stone re-used, possibly even re-cut. However, at least it gives a date before which the stone must have been quarried.

A report recent(ish) archaeological work at the Palace of Westminster records that: -

'The stone found in both contexts [15] and [19] is associated exclusively with Roman ceramic building material which would strongly suggest a Roman date. …….Of particular interest is a solitary fragment of Reigate Stone rubble from context [15]. Reigate Stone (from quarries in the neighbourhood of Reigate and Merstham [sic.] in Surrey) is rarely found in Roman levels in London, although it is common stone type in the medieval period.'
(Betts, 1996,p16)

It would be nice if the source of the stone could be identified a little more precisely than 'the neighbourhood of Merstham and Reigate'. A few years ago a report was published on an attempt at provenancing Reigate Stone samples held by the Museum of London using geological methods (de Domingo, 1994, p240-243). Although it proved possible to distinguish samples from Firestone strata from those from Hearthstone layers and which samples were from the same source, it proved impossible to identify precisely what the sources were. This should not be too surprising given that only one mine seems to have been visited - apparently Quarry Dean, from the grid reference quoted: TQ 299 538. However, to be fair, it is possible that surface samples were collected from elsewhere.

Hence it seems that, if building stones from archaeologically dated contexts are to be useful in dating individual mines and parts of mines, more work is required on petrological variations of the stone from different parts of different mines. Unfortunately I doubt if this is feasible for amateurs; de Domingo used X-Ray Diffraction, Scanning Electron Microscope and Inductively Coupled Plasma emissions Spectroscope techniques in her study and that, as has already been noted, had only limited success.


Betts I. (1996) 'Building Material Assessment' in Cowie R. New Palace Yard, The Palace of Westminster - An Archaeological Post-Evacuation Assessment, Museum of London Archaeological Service.

De Domingo Christina (1994) 'The provenance of some building stones in St Mary Spital by geological methods' in London Archaeologist Vol 7 No 9 pp 240-243

Hatton Martin (1977) 'New Dating Evidence from Merstham Firestone Quarries' in Pelobates No 31 pp 15-17

OS (1963) Field Archaeology - Ordnance Survey Professional Papers No 13, HMSO

Martin Hatton