So this may be intended and maybe I just don't remember stone counting as dirt; however, with the new system where you can auto-fill land (that needs to be raised) or auto-fill a stockpile with land you are digging (using the survey tool) you can apparently use stones (such as flint) as dirt.
While laying down some roads (made of flint) over some freshly flattened terrain, I noticed that after the soil stockpile (which was made up of dirt and worms) was finished (completely used up) the game was taking stone from my flint pile and using it as soil (which I did not intend.)
Again, I may just not remember that stone counts as soil, I rarely make it far in the Worlds before being run off; however, I found this a little disheartening that my flint stockpile was being used as soil by the auto-survey so figured I would post this here in case it was unintended that stone was being used by the survey feature.
I understand that the new feature will count worms (or anything else) inside a dirt pile; was just unaware it would eat into stone stockpiles (that contain no dirt) that were within the vicinity.