Crusty 2ndC Roman silver coin, needs a good cook to remove horn crust.
Mark says: Trajan or Hadrian – I can make out “…[A?, R?] IAN…” on the obverse and the silhouette could be either of them, I guess.  On the reverse I believe I can make out …COS II[?] which would make Hadrian a little more likely.

Obverse: ...[A?, R?] IAN...
Reverse: ...COS II[?]