Monotone normality, measures and hyperspaces

We show that a compact Hausdorff, hereditarily Lindelöf, monolithic, monotonically normal space has a monolithic hyperspace. This generalises a result of M. Bell for ordered spaces. A consistent example of a nonmonotonically normal space with a monolithic hyperspace is given. We also show that every monotonically normal compact space is measure separable in the sense of Kunen and Džamonja.