VAST EARTHWORKS. "Darwin described the volume of soil that earthworms swallow and eject as castings, or earthworm manure, and he reported that an acre of garden soil could contain more than 50,000 earthworms and yield 18 tons of castings per year. He studied earthworms’ ability to bury objects of every sort—from handfuls of chalk scattered on the ground to Roman ruins that had, he believed, been preserved for archaeologists by an industrious earthworm population." https://lnkd.in/eSjBc5w View in LinkedIn