Best of luck Juamei, it’s a tricky one, the nearby sarcens have so many natural cups they’ll try and befuddle you, but I’d think you’ll know it when you find it. The cups are much shallower than the ones you saw up here, and they look ground out rather than pecked. The main thing that distinguishes them from the natural features is that they are totally circular. It’s slightly bigger than a 3-seater sofa and slopes to the south west. It also has the ‘slug’ mark near the turfline on the southern side. I wish I'd put some photos up that showed it from a wider view. I'd do so now, but they're on a CD somewhere on the disc-mountain next door :(

It would be an excellent thing to get a proper gps ref for those cup marks, happy hunting :)