On one of our tours of the site Yuval told us that every archaeology student gets told about stratification. They are showed a diagram that shows the levels of a dig. Here is a Greek level, and above it a level from the Roman era, and on top of that is the Byzantine.
Now, look around, Yuval said. Under this one tarp you can see an Iron Age wall, a Byzantine wall, and a military trench from the 1948 War of Independence. They are all at the same level.
Good luck, archaeology students!
But at the other extreme, look at this photograph. As Terri says, it doesn't seem real, but like a drawing for that archaeology class. See the neat layers fo floor on top of floor? That is how it was found at Ramat Rachel. Now go to the next blog entry for a closeup.