... migrating across the surface of Mars. e Earth After Us What Legacy Will Humans Leave in the Rocks? Jan Zalasiewiczwith contributions fromKim Freedman1 e Earth After Us THE STRATA MACHINE29intelligence, ... changing its shape, and looking almost like a living creature as it travels. e whole thing is powered by gravity, just like the water in a fl owing river, the sediment being kept suspended in the ... living in caves, shaping rocks as primitive tools and wearing the skins of other mammals that they have killed and eaten. In the oceans, we might envisage seal-like rodents and, hunting them,...