Dissolve the sugar, Jell-O and salt in the boiling water. Drain the cherries and reserve the syrup. Add enough water to the syrup to make three-fourths cup, although according to my grandmother, they are giving fewer cherries than before and more syrup, so you may not have to add any water. Add the syrup and lemon juice to the Jell-O. Chill until very thick, then fold half of the cherries into 1 cup of the gelatin. While it is chilling, spray the mold with cooking spray and if it is the kind with the bumps, place a cherry in them. Pour the chilled gelatin with the cherries into the 1-quart mold. Chill until set but not firm.
Meanwhile whip the remaining gelatin (it should still be liquid) until fluffy then fold in the cream, the remaining cherries and marshmallows. Spoon into the mold and chill until firm. Unmold and serve on greens.