Explain SMBC — the wiki for Saturday Morning Breakfast Cereal

This comic shows someone standing near what appears to be a peat bog, being asked "What's in the sack?" They respond with a deliberately bizarre list: "A platypus skeleton, 3 wheels of cheddar, a clay tablet with Euclid's axioms on it, and precisely 53 dildos." The caption reads "Weekend Activity #98723: Putting weird stuff in peat bogs to confuse the future." The humor comes from the fact that peat bogs are famous for preserving organic material for thousands of years (like the famous bog bodies). The comic imagines someone deliberately planting absurd combinations of artifacts to baffle future archaeologists, who would have to try to construct a coherent narrative about a civilization that buried platypus skeletons alongside sex toys and mathematical tablets.