The Hemiassarion denomination
The hemiassarion was a bronze denomination worth ½ as - assarion in Greek.

It was commonly struck by Roman Provincial mints, and was not struck to a standard weight but rather to some local standard. It was simply a coin worth ½ of the local basic coin denomination.
Hemiassarion

(1) Geta 198-209 AD
Obverse: draped bust right from behind; Π CEΠTI_ΓETAC K
Reverse: tripod, snake entwined around leg; MAPKIANO_ΠOΛITΩN
Ref: Varbanov I 1117; AMNG I/I 703