"A usually rounded earth surface lower then a mountain" Websters'. A mountain to me is at least 1,000 feet above anything around it so . . . For grade I would need to drop out of the big ring. If you are just going up and down a hundred feet or so I'd just call them rollies and ignore them.

For contrast just look at the highest point in kansas, mt. Sunflower

http://americasroof.com/ks.shtml