Your post and placemark are very interesting.
The "oval shaped tree mass" has the shape of an amphiteatre, and the dimensions (100m x 85m) are very close of others amphiteatres, for exemple Spello (115m x 85m) or Asisium (107m x 82m).
The town is not in fact Talacchio (an industrial area at the north-east) but the little medieval town of Colbordolo.
I tried to get information on the story of Colbordolo :
http://www.comune.colbordolo.pu.it/
but they do not speak about roman buildings, just medieval "borgo" .
As you speak italian, you should send an e-mail to the town to get informations : comune.colbordolo@provincia.ps.it

best regards
H21