Ury House -- 1899
The fort was so massively built of stone that in 1899, when it was necessary to make some interior changes in Ury House, the workmen had to use dynamite to make any impression on the masonry.
Harold Donaldson Eberlein and Cortlandt Van Dyke Hubbard, "Colonial Philadelphia No. 13 Ury House" (Evening Public Ledger, 1939.10.03).
So solidly was the fort built of stone that when some changes were made at Ury in 1899 dynamite had to be used to make even a dent in the masonry.
Rex Rittenhouse, "Ury House Guest Was Victim Of Jittery Maid" (Philadelphia: The Evening Bulletin, 1945.10.21).