Juamei, most likely they are. Looks like a chain of pyramidical smallish mountains, you'll see them from the Worcester area of the M5 looking westwards.

Anyone care to piss off a lot of people and list all the major earthworks visible from the M5? ;-) Bredon Hill, Whittington Tump, bloody big one near Crooks Peak can't remember, Glastonbury Tor (watch out you'll crash)

aharghya!

That's the one.
There are a lot of reasons to get distracted all down the M5. Glastonbury Tor, just peeping above the Somerset Levels, is the one that'll do for me in the end.
Maybe blinkers are the answer.