Please help to identify Roman Coin (Carausius ?) [solved]

Weight ± 2.39 g
Diameter ± 18 mm

Interesting. The obverse legend reads IMP C CARAVSIVS, which is somewhat odd because one expects P F AVG at the end. Check the Wildwins page for Carausius.

The engraving of that legend is also quite clumsy. I suspect this is a (semi-)barbarous imitation. There is a single example of a coin on the Wildwinds page which is described as “semi-barbarous”. Not your coin, but as you can see, the legend is problematic.

Thank you very much for your help; you have helped me a lot. This is definitely a (semi-)barbarous imitation.

I think this is the reverse type it copies, PAX AVG, Pax holding long branch and cornucopia, this is from plate 6 of, Carausius, A consideration of the historical, archaeological and numismatic aspects of his reign by Hugh Williams.

I think you're right, and based on this Google Images search, it looks like barbarous imitations are not uncommon for Carausius.