The C mint of Carausius was responsible for a number of types of antoniniani where the bust of Carausius was presented left facing jugate with that of Sol. It is apparent from the reverse marks that they were produce in more than one period.
Over the years I've encountered a number of specimens of these types and these are recorded below.
-/-//MC (c.288-9 AD)
INVICTO ET CARAVSI AVG
FORTVNA
Fortuna seated left holding cornucopia
-/-//MC
Hansons, (Apr?) 2022, lot 182, Roma XXV, 23 Sep 2022, lot 1070
INVICTO ET CARAVSI AVG
FORTVNA
Fortuna seated left holding cornucopia
-/-//MC
Spink N.Circ 102 (Jul) no.3900, ex Albert Baldwin sale. Noted as C minmark in Spink publication, however it is the same reverse die as on the coin above that clearly shows MC in exergue.
INVICTO ET CARAVSI AVG
FORTVNA
Fortuna seated left holding cornucopia
-/-//MC
Ex eBay UK, currently in a private collection
-/-//CXXI (c.289-90 AD)
SOLI ET CARAVSIO AVG
PAX AVG
Pax standing left holding branch and vertical sceptre
-/-//CXXI
BM 1989,614.1
IMP CARAVSIVS PF AVG
PAX AVG
Pax standing left holding branch and vertical sceptre
-/-//CXXI
BM 1853,0329.29
IMP CARAVSIVS PF AVG
PAX AVG
Pax standing left holding branch and vertical sceptre
-/-//CXXI
Ebay, February 2007
IMP CARAVSIVS PF AVG
PAX AVG
Pax standing left holding branch and vertical sceptre
-/-//CXXI
Hunter 109
IMP CARAVSIVS PF AVG
PAX AVGVSTI
Pax walking left holding branch and sceptre
-/-//CXXI
R Bourne collection
IMP CARAVSIVS PF AVG
PAX AVGVSTI
Pax walking left holding branch and sceptre
-/-//CXXI
Hunter collection, GLAHM:32112 HCC IV 110 (not illustrated); line drawing in Kennedy (1756)
IMP CARAVSIVS PF AVG
VIRTVS AVG
Mars stg right and leaning on shield
-/-//CXXI
BM 1992,0635.1
The online BM description of the reverse is VIRTVS AVGGG with a mintmark -/-//C. This cannot be the case as the obverse is a die duplicate of other CXXI coins that predate the three emperors issue.
S/C//C (c.291-2 AD)
IMP C CARAVSIVS PF AVG
PROVIDEN AVG
Providentia stg left holding baton and cornucopia, globe at feet
S/C//C
BM 1966,0607.1
IMP C CARAVSIVS PF AVG
PROVIDEN AVG
Providentia stg left holding baton and cornucopia, globe at feet
S/C//C
Casey (1994), plate 5, no.2
IMP C CARAVSIVS PF AVG
PROVIDEN AVG
Providentia stg left holding baton and cornucopia, globe at feet
S/C//C
Lanz, 20 November 2000, lot473, also 25 May 2002, lot 830
IMP C CARAVSIVS PF AVG
PROVIDEN AVG
Providentia stg left holding baton and cornucopia, globe at feet
S/C//C
Hansons, (Apr?) 2022, lot 183, Roma XXV, 23 Sep 2022, lot 1067
IMP C CARAVSIVS PF AVG
PROVIDEN AVG
Providentia stg left holding baton and cornucopia, globe at feet
S/C//C
DNW, 14-15 Nov 2018, lot 1414
IMP C CARAVSIVS PF AVG
VIRTVS AVG
Mars advancing right holding spear and shield
S/C//C
BM 1863,0325.4