Kimmeridge is good but these are mainly the shale impressions that crumble easily, plus you have to pay to enter the track to the cliff top car park, as it is owned by an Estate.
Charmouth is good, get to the main car park, then head East as far as you can away from the crowds, good for Bellamites and Ammonites. First Ammonite my son found there years ago , we weren`t exactly sure what it was because it was virtually Gold in colour, only when fully extracted realised it was a fossil.
Would recommend out of season though, as parking fills up very fast. If you are there for a few days in season, suggest getting there before 9am.
Good Luck,
Dave.