vintage Imperial horizon blue (ice blue) carnival glass round covered butter dish w/ flower

Flower pattern (daisy or cosmos?) pressed glass round butter dish, pretty ice blue colored carnival glass. I've been told that Imperial made this pattern, but I don't know the pattern name, or it's exact vintage.

This measures about 7 1/2" across the plate overall, 4" across the well. Both the plate and the dome cover are in very good condition, no chips or damage, color looks great.