Abstract The goal of this study is to determine the geological character and source of the exterior stone stairs that once ascended to the south entry at Stratford Hall on the Potomac River in Virginia. The intent is to clarify the date and physical history of these stairs by determining their geologic source. Built for Thomas Lee beginning in 1738, the hall was restored in 1929–1940. At that time the stairs of the south entrance were red sandstone. These early stairs were dismantled during the restoration and stored onsite. As part of the present study, we thin-sectioned the stored stones and compared them petrographically with samples of other red sandstones used around the Chesapeake Bay in the colonial period, including Seneca sandstone from Maryland and St. Bees sandstone from England. The Stratford stairs are made of lithic arkose, which resembles Seneca sandstone significantly more closely than St. Bees sandstone both in mineralogy and in grain size. If the Stratford stairs were made of Seneca sandstone, that would push their installation date forward to at least 1802, when the Patowmack Canal on the Virginia side of the Potomac River allowed transport of Seneca sandstone by boat, avoiding the falls on the river. A more likely even younger earliest date is 1832, as that is when the improved Chesapeake and Ohio Canal was functioning on the Maryland side. This has implications for decisions about the restoration of the mansion.
Key et al. (Thu,) studied this question.