The Great Karoo was formed in a vast inland basin starting 320 million years ago, at a time when that part of Gondwana which would eventually become Africa, lay over the South Pole. The Karoo records a wonderful time in our evolutionary history when the world was inhabited by interesting amphibians and mammal-like reptiles — including the apex predators of the day, the Gorgons.
Gorgons or Gorgonopsia were sabre-toothed therapsids who roamed our ancient Earth from the Middle to Upper Permian — 265 to 252 million years ago — with their long claws, lizard eyes and massive canines. 
I learned about the Karoo, and indeed the Gorgons, by a book of the same name by the deeply awesome Peter Ward. His introduction to what life and fieldwork are like in the arid, inhospitable ancestral home of the Gorgons made me laugh out loud in glee. I highly recommend you read it, too.