Never underrated here, for it is the very home of me, and was of course the last stronghold of the last pagan king of England. Still trying to source a copy of the following film (worth a read if you have the time) as it's burning my memory moreso.

http://www.elidor.freeserve.co.uk/pendasfen.htm

Hard core of Malverns is 680 million years old (Pre Cambrian), igneous metamorphic rock. Here's a link to a special report

http://www.bbc.co.uk/herefordandworcester/realmedia/2003/04/malverns_quarrying.ram

And imagery:
http://www.bbc.co.uk/education/rocks/programmes/prog2.shtml

British Camp is a world feature in my opinion, and the numerous holy springs/wells still taste as good as I remember. One called 'Eye Well' has specific healing properties, according to legend. It's no great leap of imagination to imagine how awesome this place was in the middle Bronze Age, rising out of the Severn Plains majestically, abundant with all the the things needed for life and luxury, affording views to Wales and the Cotswolds. It is verily the roof of England with Sabrina running by.