Part III, on _Lepidodendron_, deals partly with stems referred to _L.

Harcourtii_, but now separated as _L. fuliginosum_. He also describes the structure of a _Halonia_ and is led to the conclusion that it is the root of _Lepidodendron_. This view has not found favour, but our old ideas about _Ulodendron_ and _Halonia_ have been so upset of late, that everything seems possible!