dnd 5e – What happens if a druid is wild shaped as an Earth elemental and gets turned into stone?

In a D&D 5th edition game I’m running the PCs fought against Gorgons. The druid was wild shaped into an earth elemental (moon druid). The druid got turned to stone by failing two saves in a row to the gorgon’s breath. What happens in this situation?

Is he a statue of a an earth elemental, or a statue of a druid?
If he is an earth elemental, could you break the statue, doing enough damage to kill the earth elemental but not kill the druid, and would that free him, or just turn him into a statue of a druid instead of an earth elemental?

I can’t seem to find rules on this anywhere.