to Isle of Wight History CentreWhat are the Moons Hill Structures?

Over the years there has been much speculation as to the origin of these oddities at Freshwater, frequently referred to as ice houses. The concrete structure is not part of the original site but was built over them when they were first excavated in the 1890's, at which time they were said to be pottery kilns or cremation ovens. Our own site survey and examination of previous evidence suggests none of these theories are valid Moons Hill image

The Original Excavation
The earliest known record of these structures is that of Robert Walker who discovered and excavated them in the 1890's. Walker was an ardent advocate of the theory of ancient Island tin trading. He published a booklet on this theory called Phoenicia in Freshwater [Newport Reference Library] and recorded his excavation of this site in the booklet on the assumption it had Phoenician associations. Whilst the record of his excavation must be of interest in any analysis, his interpretation of what he found is less reliable. The ancient tin trading theory is now generally discredited.

What he discovered were not structures as such but sculptured pits dug into the top of the bank with entrances through the front of the bank. There were no building materials used as the surrounding clay had fired itself into a secure terracotta wall. His enquiries revealed that, prior to earlier road widening, there were 2-3ft entrances. Following his excavation Walker built the concrete domes and bricked entrances to protect them from vandalism. Their final appearance was the result of some speculation on Walker's part as to the original shape. His findings can be summarised as follows:-
  • The pits filled with a stiff clay
  • In excavating the clay he found it interspersed with charcoal and containing pieces of curved terracotta 'wall'.
  • Near the bottom, a floor of crushed stone
  • In one pit, under the stone, a 'white waxy' material interlaced with layers of charcoal. He says this material tested as phosphate
He suggests they are pottery kilns but explains the phosphate as cremated animal bones. He claims the domed tops are the original shape, based on the curved pieces of terracotta he found during the excavation. Walker associates the kilns with ancient tin trading by interpreting two marks on the interior as classic Greek lettering, and stating the excavated clay and stone were not local materials but from the same West Country direction as the tin source. He also interprets a chemical analysis of the internal vitreous surface as a sophisticated applied glaze.

Any antiquarian examining these pits would have to consider the possibility they were lime kilns. Walker does so but rejects the idea at the outset by saying the vitreous internal surface was in too good a condition to represent a lime kiln. Thereafter he was at pains to dismiss any further evidence pointing to lime kilns. The workers who originally widened the road told him they found 'common lime' at the entrance to the kilns. He dismisses this as a misinterpretation due to their 'unscientific minds'.

Site Survey
The suggestion they are ice houses is based on their appearance today rather than their original state. Our own survey quickly established they are not ice houses: there is no drain and the entrance is too low (subsequent road building has raised the base level of the entrance). They are almost certainly kilns of some sort. The interior has a vitreous coating, presumably as a natural result of repeated firing. The sides have a slight bowl shape, narrowing at the top and towards a ledge surrounding a furnace at the base. The dimensions of the western kiln as follows:
Height from furnace to top (as originally discovered): 2.31 m
Diameter at widest point: 2.51 m
Diameter at base above ledge: 2.34 m
Diameter of bowl (furnace): 1.83 m
The eastern kiln has similar proportions but is approximately 18% larger all round.
The immediate impression is that of lime kilns.
Walker rejected this possibility on the grounds the condition of the vitreous surface was not typical of a lime kiln. This condition arises in kilns as salts are extracted from the walls and fired into a glaze. The glaze varies depending on the wall material and firing temperatures. It was a little presumptuous of Walker to reject a possibility simply because he hadn't experienced this particular condition before. As lime kilns they probably had some sort of raised level above the bank closing the top slightly. The curved pieces of terracotta wall found when excavating the pits could represent a concaved top, rather like the dome shape but with the top half cut off.

Cross section of a kiln
As first discovered
kiln 1
The bank had been cut back to the front of the kilns. This probably resulted in the face being slightly shaved off, thus destroying evidence of the entrance height
Probable original design
kiln 2
Shows the bank extended and the earlier lower road level. The raised top would account for curved pieces of 'wall' found during Walker's excavation

These kilns resemble the 'flare' type of lime kiln. A grid would have been place on the ledge at the base, arched upward at the entrance, and the chalk stacked up over this, loaded in from the top and up to the top. The fire would then have been ignited in the pit below this through the entrance (the draw hole). The draw hole may have been packed to control the draught and allow it to burn for four or five days.
The inside of the kiln with the ledge running around the base. The remains of the green glaze surface of the walls can be seen. Note the white material fused to the base at the right just below the ledge.
Model of the lower section of a lime kiln at Guilford Museum. Built into a bank, it's similar in design to the Moons Hill kilns, showing the ledge around the base and the entrance through the bank.

Chemical Analysis
The only material remaining in the kilns today is a deposit in the western kiln that is fused to the base below the ledge (see above photo). We had this chemically tested and it proved to be limestone - exactly as would be expected in a lime kiln.

Analysis of material found in kiln base
Sample AEIBVlOW~DO1 was analysed for major chemical composition using Energy bispersive x-ray Spectmscopy (EDS) and crystalline phase I structure identification using X-ray Diffraction (XRD).
EDS analysis:
 Chemical analysis showed the sample is composed of calcium, carbon, silicon and oxygen.
XRD analysis:
 Crystalline phase identification confirmed the chemical analysis, demonstrating that limestone mineral calcite (calcium carbonate) is the dominant material. Quartz (silicon dioxide) is also present, along with small traces of illite clay (alumina-silicate), and gypsum (calcium sulphate). This is shown graphically in the attached diffractogram

There is no trace of the material Walker identifies as phosphate. Our enquiries with experts in chemical composition suggest there is no 'white waxy' material that could be identified as phosphate and cremated bone would not end up in that state. The most likely explanation is that, whatever the material was, it contained merely a trace of phosphate and this was misinterpreted.

dig picture We excavated a 3 x 2 metre area on the bank at the rear of the western kiln. It revealed little. There was a 7cm deep level of disturbed clay below the topsoil and directly on natural level. This contained fine builders debris apparently associated with the building of the domes. Occasional lumps of chalk were present particularly near the base of the dome. In general it would seem the builders of the concrete dome left a very tidy site.
Had these ever been pottery kilns even the cleanest of sites could be expected to reveal the odd piece of waste material, particularly as the kilns were apparently excavated onto the bank. We found nothing, just as Walker does not record any. It's therefore difficult to see how these could ever have been interpreted as pottery kilns.

In the absence of building materials or finds, dating them is not possible. Many local people were aware of Walker's excavations at the time yet apparently none could supply anecdotal explanation for the kilns. This would seem to put their latest possible date as the end of the 18th century or very early 19th century. Lime kiln design tells us little as such basic design remained unchanged for centuries. If they were created to provide field liming, rather than building material, they would be later rather than earlier. Farming lime kilns were not widespread until the 17th century. The earliest tithe map (1837) shows all the surrounding land to be arable farmland, suggesting a need for considerable liming.

The derivation of 'Moons Hill'
In the 13th century lands in Freshwater were held in the name of William le Mone. The use of the French definite article, le suggest this name refers to a professional or personal characteristic of a previous family member. If le Mone came from the French le Moine it thus translates as 'The Monk'. Monastic connections with the area are still evident from Monks Farm and Monks Lane between Norton and Colwell Bay and probably derive from lands acquired by Beaulieu abbey in the 13th century. Also Freshwater church was one of six Island churches granted to the Abbey of Lyre shortly after the Norman Conquest. Of course the monk in question must have abandoned his discipline to produce a family. Although the the Mone family name was no longer recorded in Freshwater after the 16th century, lands continued to carry the name, as in Mones, Mones Close and Mones Mead. By the end of the 18th century Mones had transmuted to 'Moons' or 'Moon', and Moon Lane eventually became Moons Hill.

CONCLUSIONS There seems little doubt these are lime kilns. A pair built into a bank is quite typical. This conclusion differs from that of Walker's but is not entirely at odds with what he found. Some anomalies might point to the kilns ending their life in a use beyond their original purpose. The considerable increase in farming lime kilns during the second half of the 18th century makes that period the favourite for these kilns, but it's by no means certain.

December 2000