underarm: unknown hand and type
J. Martin (Essex cricketer) Wikipedia
J. Martin (first name and dates unknown) was an English first-class cricketer with professional status who was mainly associated with Essex and is known to have been active from 1785 to 1794. He also played for Middlesex and the White Conduit Club. Principally a bowler of unknown hand and pace, Martin made ten appearances in matches rated first-class by CricketArchive, totalling 107 runs with a highest score of 29 and taking 33 wickets. He is recorded in four other matches.
Martin's association with the White Conduit Club suggests that he was probably a professional ground staff bowler there. Until the works of Samuel Britcher came to light in recent times, Martin's initial was unknown but a 1790 scorecard in Britcher confirms that he was J. Martin.