The detritus of past civilizations.
2001. "But of course: no clutter. No newspapers, no renegade scraps of domestic detritus, no rubber bands, paper clips, coupons, pens or pencils, notebooks, magazines. No knives. Where were the knives?" — Chip Kidd. The Cheese Monkeys.
An example of detritus is small pieces of shale broken off by erosion.
An example of detritus is the leaves that have fallen from a tree in winter.