To answer this question, I will define interesting as unusual or unexpected.
My students and I were examining and describing a soil profile, a vertical cross-section of soil, in other words, a hole that is about 2 m deep x 1.5 m side x 3 m long.
We saw an elongated, white object at about 1 m below the surface. It did not look anything like any soil I ever observed, so we looked more closely. It appeared to be made of wood, so we began to dig it out.
It was a folding chair!
There had been a major flood about 30 years prior, and several minor floods since. Apparently the chair washed away from someone’s yard and was carried to that point. Somehow the sediments began covering it before it could float to the surface. Perhaps it became waterlogged, and had just enough metal to overcome the wood’s buoyancy. Whatever, it was covered with sediments. It looked as if most of the sediments (up to 75 cm) were deposited in that same flood.