Capítulo 1750: 1750. Seeds And Rotting Wood

Stagnant water had seemed to pool here and there as Walker looked at the random dips. "What causes these random dips in the ground? It doesn't look like it's shifting from the mountains shifting. I would assume trees, but these places seem to be missing trees." Since Walker wanted to know, Seran and the other angels that heard his questions were fine with explaining the difference in the terrain. They had come through here many times and needed the knowledge to survive. 

"It's actually from where trees used to be. The monsters and insects eat away tree stumps from fallen trees. Then the space is washed away by water. After all the roots and stump are gone, this is left. Rocks are exposed making larger and larger pits as more water pools."