Archaeological Investigation

Fine shelly beds in stone used for the restoration

As a geologist, with specialist interests in the building stones used in historic structures and experience of their restoration – as well as possessing a good eye for detail – I have always thought that I could make a very useful professional contribution to the work of archaeologists.

Various stones used in the construction and restoration

A quick walk around the exterior of St. Peter's church, in Conisbrough, shows the variations in the Permian dolomitic limestone used in different parts of the building – representing the masonry techniques and quarry sources used  from the 12th to the early 20th century.

When undertaking stone matching, it involves a detailed inspection of the building, where there may be various phases of construction or restoration - with subtle variations in the colours and textures - and sometimes the stone is completely different.

The Victorian restoration obliterated so much of the external fabric of the church that it is often difficult to positively identify the original mediaeval masonry and, in places, Carboniferous sandstone has been used to restore the limestone ashlar.

Restoration of the 15th century chancel with limestone and sandstone

 

Having only visited St. Peter’s church for my own pleasure, and taken a few photos on the sunny sides of the exterior, I have never had a reason to undertake a hydrochloric acid test or examine the stones through my hand lens, as I would normally do as part of my professional work.

Roughly squared and ashlar walling from the 14th and 15th century

I have not yet studied the Victorian and Edwardian additions to the dark, north side of the church and I am interested to see if the stones used here are similar to those used to restore the south aisle and tower - with differential weathering exposing distinctive ripple marks and highlighting very fine shelly beds. These look more like the Jurassic limestone of Lincolnshire than the dolomitic limestone that I have seen in very many places.

Ripple marks in limestone used for extensive restoration