Standing between the main school buildings and the Sixth Form boarding houses is an industrial relic that indicates how the land was once used. The lime kiln has been a familiar feature of the grounds of St Mary’s for generations of pupils. It is now no longer open for the girls to climb but at one time pupils used it as a performance space and for relaxation.
Calne lies on a type of limestone made of petrified coral known for its richness in fossils. There were several small quarries around the town and four lime kilns are recorded of which the one in St Mary’s is the only surviving one. It is a listed building.
During the 19th century the area around the lime kiln was a quarry. Extractions were used for building and agricultural purposes, burning limestone being one of the processes. Originally the quarry was divided by a north-south wall with the west side owned by Lord Lansdowne and the east by Dr Ogilvie who lived in Curzon House, now part of St Cecilia’s, one of the boarding houses. When Lord Lansdowne bought Ogilvie’s quarry in 1869 the wall was demolished and the combined quarries were known as Piece Quarry. Towards the latter half of the 19th century, limestone extraction ceased and the quarry area was used for allotments. Arthur Dunne KC, one of St Mary’s Governors, bought the land for the school in 1919 from Lord Lansdowne for £338 and it was turned into a games pitch, but the lime kiln remained. The sides of the quarry are still visible within the grounds and for many years an area behind the lime kiln contained ponds which were used to collect biology specimens. Deemed unsafe, the ground was filled in in the 1960s, planted with willow and balsam and grassed over for recreational use. St Mary's Sixth Form houses stand there today.