You should look for beeches.
Then you will find a basalt deposit in the sandstone.
It is not clear whether it is a question of former mining or a basalt quarry.
From here towards the E-wing wall there are an enormous number of fallen trees that you have to climb past or over. It's strenuous and not entirely safe. In some places it's not at all clear if and where the path continues (12/2024). Not recommended.