Exactly. This is hard to understand when living in a flat in a modern city but i...

		pmontra 65 days ago \| parent \| context \| favorite \| on: Four strange places to see London's Roman Wall Exactly. This is hard to understand when living in a flat in a modern city but it's immediately clear in any other case. My figure of 1 mm is about the compacted result of decaying and layering. It may vary a lot according to the configuration of the ground.