Gloucestershire 193 and 282 for 9 (Marshall 83, Jones 55) lead Kent 235 (Coles 66, Haggett 54, Norwell 4-44) by 240 runs
Having bowled out Kent, finally, for 235 in the morning session, Gloucestershire found themselves staring down the barrel of defeat, inside three days, as Darren Stevens and Ivan Thomas reduced them to 81 for 4, shortly after lunch.
However, Marshall and the former Kent wicketkeeper Jones added 134 for the fifth wicket to give Gloucestershire the chance of winning a third successive Championship game.
Resuming on their overnight total of 223 for 9, Kent lost their last wicket when Adam Riley top-edged a pull shot, off the bowling of Liam Norwell, to wicketkeeper Gareth Roderick. It was Norwell's 32nd first-class wicket of the season and left him with the impressive figures of 4 for 44 off 24 overs.
On a wicket that provided the bowlers with a degree of encouragement, Gloucestershire batted well in the early stages of their second innings. Openers Chris Dent and Roderick put on 59 for the first wicket with both batsmen looking set for the day. However, the introduction of Darren Stevens turned the game back in Kent's favour as Gloucestershire preceded to lose four wickets for just 22 runs in 9.3 overs.
Dent, who struck three boundaries in his 48-ball stay, was first to go, when he played on to a regulation delivery from Stevens. Eight runs later, off the final ball of the morning session, Ian Cockbain became victim number two for Stevens. That was 67 for 2.
If the final throes of the morning session were disappointing, for Gloucestershire, the early stages of the afternoon session were equally as frustrating. First, Peter Handscomb flashed at a short and wide delivery from Thomas and was duly caught by wicketkeeper Sam Billings. Then, Roderick departed in similar fashion, caught at slip by Stevens, once again off the bowling of Thomas.
Thankfully, for Gloucestershire, Marshall and Jones batted with far greater application to add 134 for the fifth wicket. Marshall passed 50 off 84 balls and reached 13,000 first-class runs, courtesy of four overthrows. Jones, who signed a two-year contract in the winter, reached his half-century off 92 balls, with six fours.
Marshall eventually holed out to Fabian Cowdrey at backward point off the bowling of Matt Coles, for 83, before Kieran Noema-Barnett departed without scoring and Jones for 55, trapped lbw by Thomas. Craig Miles and David Payne put on 36 for the eighth wicket as Gloucestershire finished the day on 282 for 9, leading by 240 with one second innings wicket in hand.