>>939367015
and as another example of layers of stuff being done by people as well as natural processes, here is a photo of a ship, dated to about 1770 found underneath the wreckage of the World Trade Centre. The WTC towers are about 400m from the shoreline of Manhattan island today - but in the 1770's, that was the shoreline. 400m of land has been added by dumping rubbish into the water's edge constantly for 250 years, and doing stuff like scuttling old ships and using them as foundations, filling in the hull like its a giant wooden bucket.