A Detroit man is being held at the St. Clair County Jail after his arrest this week by the St. Clair County Drug Task Force.  The 30-year old was taken into custody after a bust in which deputies seized crack cocaine and about $500 in cash.  The man was already on a tether probation for a felony drug conviction in Macomb County.  The bust took place Wednesday along the 1700 hundred block of Michigan Road in Marysville.