A reader asks:

This is probably a stupid question, but why are so many ancient ruins buried? In the year 3000 is some archeologist going to dig up the lost city of Washington D.C.?

Note: As I suspect definitive answers to this question very quickly, watch this space for an announcement that the window to send me emails on this subject has closed.

Update: Lots of email. But these two links seem to have all the answers most will need. Here and here. It’s pretty much what I thought, but when I guess on things like this I hear about it for weeks.

Oh and this reader adds:

I’ve got a deadline and don’t have time to answer in detail (but just enough time to scan NRO), but I am your archaeology guy — perhaps the only professional archaeologist among your regular readership. You can sum it up as:
Flood deposits.
Eroding soils moving from point A to point B.
Wind-borne soils.
Trash (including tearing down old buildings and putting up new ones on top of the remains).
Surplus paper generated by that hallmark of all great cities — a bureaucracy.

Though I doubt he’s the only archaeologist amongst our readers.