Britains Historical Ruins

[pdq1]

Where did all this extra earth come from? When they dig down to Roman ruins they are usually covered with at least 2'of earth. That was about 2000 years hence. When looking for dinosaur bones they dig even deeper.

[LazyGun]

Its quite an old article, but this one I think pretty much answers your question regarding archeological dig sites etc.

As far as fossils are concerned, not all such sites have to be dug out - shale beds for instance, or the UKs very own "Jurassic Coast" in Dorset - very rich area for fossils, and no digging required ( to speak of)

http://www.straightdope.com/columns/read/813/how-come-archaeological-ruins-are-always-underground

[jno]

dust, rubbish, volcanic lava... 2000 years is a long time

[VHG]

Note these roman ruins are often just the foundations. So they are digging down to what was already undergorund when the building was still there.

Rarely do "above surface" walls survive in things like roman buildings, only in perhaps castles. Sometime floors are just below the surface.

With many old buildings the stones above the surface were "robbed" to go to build other buildings nearby, and even the foundation walls can be robbed out so all that remains is the earth infill of where the wall was.