Is it possible to find lootable dirt walls in the Underground?

I was playing a bit of Terraria, and suddenly, I found a campfire in the underground. I read you could find them with some money, but it was generated in a very strange way, and what surprised me the most, was that when I tried to destroy the dirt wall, the wall fell, and I was able to loot the dirt wall: is this something normal or is it rare?

It should be impossible to loot a natural dirt wall in any version of Terraria. It might be possible that a campfire was spawned in an underground camp, although the weird generation doesn't make sense. Is is possible that you accidentally broke wood walls or something similar? If this is not the case, then the only way you could collect loot is if they are instead crafted dirt walls as opposed to natural ones. This may have occurred during generation, or you may have placed them long ago and forgotten about them.