GEOARCHAEOLOGY OF THE COLONIAL ERA STONE STEPS AT STRATFORD HALL, VIRGINIA

Historical architects at the colonial era Stratford Hall in Virginia are hoping to replace the current stone steps at the north and south exterior entrances with original stone. The current south entrance stairs were installed in 1935 and the north stairs in 1940. These stairs were improperly restored by Fiske Kimball to what was thought to be their original style based on Cretaceous Aquia sandstone architectural fragments recovered during archaeological excavations in 1930 that were from the garden, not the house. Kimball decided not to use Aquia sandstone due to its susceptibility to weathering and instead used the lithologically similar Pennsylvanian Briar Hill sandstone. These current stairs are now considered historically and architecturally inaccurate. Our hypothesis is that the original stairs were made of Seneca sandstone quarried near Seneca, Maryland. The Seneca sandstone is from the arkosic Manassas Member of the Passaic Formation of the Chatham Group and was deposited in the Lacian Substage of the Norian Stage of the Late Triassic Epoch. Samples from each of six remaining original south entrance stone steps from Stratford Hall, eight from Seneca quarries, and one sample from St. Bees Quarry in England, which was also thought to be a possible source, were collected and thin sectioned. From there, high resolution digital scans of thin sections were used for grain size analysis and mineralogy to determine whether any of these samples match those of the original south stone steps at Stratford Hall. 100 grains from each sample were analyzed for grain size and mineralogy, for a total of 1,200 grains. Results showed that there was not a significant difference between the Stratford Hall and Seneca quarries samples in regards to grain size and mineralogy. They were both moderately well sorted fine grained lithic arkoses. This allowed us to conclude that the original stone stairs at Stratford Hall were likely made from Seneca sandstone. Based on the history of Seneca sandstone quarrying this has implications on by whom and when these stone stairs were added.