Having lived in Italy for 7 years as a teen, the word is that construction of commercial, governmental, and private sites will be shut down for sometimes years so the Italian government and bureaucracy can have its go in deciding what action to take. A Roman era catacomb was found when my sister's school was being expanded, and the Nuns running the school managed to hush it up pretty well. I imagine they explained to the working crew their loss of a job if word got out..

It seems reasonable a similar thing happened here even as far back as the 1870s when the original construction was taking place.