All Buried GREENWICH ROYAL NAVAL CEMETERY East Greenwich Pleasaunce Park Henry Parker Captain Mark Halpen Sweny
What is the cross-and-s shape on Captain Sweny's tombstone? P.S. I assume you've seen this article about Mark and his brother? The History Press | The Sweny brothers & how they both met Napoleon
Could it be a monogram version of IHS? The Society of Jesuits were prominent in Ireland so that could be why that symbol is there? The form of the monogram has changed markedly over time. The monogram with a cross (usually springing from the cross-bar of the ‘H’) first appeared in the 1760s and enjoyed a high popularity until the 1860s