This is a partial scan of a 1978 Metrobus map produced by Arlington County. A couple of interesting things that jump out to me are the fare zone boundaries running along the left side of the page and through Arlington Cemetery, and several routes that no longer exist, such as route 10 running along Fairfax Drive in “Parkington” (now Ballston).

What do you see that’s interesting?

Somewhat larger version.
Much larger version.