During World Generation, Schist and Dacite sometimes replace grass/dirt blocks, resulting in generation like the following.

Grassy Regoliths don't properly have their grass model setup for snowy terrain.

Cannot craft stone tools with Dacite or Schist:

Except for the grassy regolith model, all is intended design.

Plants growing on those surfaces is intended? Alright, just wanted to know, does look somewhat janky.

The inability to craft stone tools with those stone types is a bit odd though as most of the other stones work correctly.