He had rolled down a declivity of twelve or fifteen feet.
Franz and the count in their turn then advanced along the same path, which, at the distance of a hundred paces, led them over a declivity to the bottom of a small valley.
Two other men descended after Danglars forming the rearguard, and pushing Danglars whenever he happened to stop, they came by a gentle declivity to the intersection of two corridors.
There are no more uses of "declivity" in the book.
Show samples from other sources
One Heart Breaking "There is a passion for declivity in this world," Tennessee Williams has one of his characters say in Comino Real. The ultimate declivity is death. But the pain that accompanies this descent in Williams’ plays is a sense of what is lost during the journey—honor, gentleness, tenderness, brotherhood, the ability to love, or even communicate with, another human being.
One Heart Breaking, Time Magazine, 1/19/70 -- http://www.time.com/time/magazine/article/0,9171,878685,00.html(retrieved 08/15/09)
Physical declivity takes her from a cane to a walker to a wheelchair.