Its 'similar' to this one (my ID): http://www.wildwinds.com/coins/ric/constantine/_cyzicus_RIC_VIII_046.jpg
Constantine I. AE4. Cyzicus. 347-348 AD. DV CONSTANTI-NVS PT AVGG, Veiled head right / VN-MR, Constantine, veiled, in shroud, standing right, hand clasped to breast. Mintmark SMKD. RIC VIII Cyzicus 46.
Had a closer look at the reverse & I can see the mint is correct as well as the legend, because I can see the 'S' & 'K' - S[M]K[D]. So I'm now 100% sure thats your coin.
Crispus AE3. 324 AD. FL IVL CRISPVS NOB CAES, laureate, draped, cuirassed bust left / CAESARVM NOSTRORVM around VOT X in wreath, dot in badge at the top. Mintmark TSDVI. Thessalonica RIC VII 125