"Rift valley" means an elongated depression, trough, or graben in the earth's crust where the central flat block forming the trough slips downward relative to the crustal blocks on either side. The appearance is that of a fallen keystone in a broken arch.
There are only two true rift valleys in the world and one of them is the mesopotamian valley in East Africa where the hominid "Lucy" was discovered.
Here is the other one...
"Escarpment" means a long line of steep cliffs at the edge of a plateau formed by erosion or vertical movement of the earth's crust.
Like the edge of the Cumberland Plateau...
"Hang Gliding Capital of the East" means there are truly crazy people who launch off of the aforementioned escarpment and hurl themselves into the rift valley below.
"Sequatchie" means "Opposum, he grins or runs"