I like this one as I can remember struggling, years ago, with trying to comprehend stone tool technology, and why the Middle Palaeolithic was so well documented in the Sahara. Okay, it's a desert and dry weather preserves things – but these are stone tools and they would be preserved even in a wet environment. This piece explains it all.
At http://archaeologynewsnetwork.blogspot.co.uk/2015/03/saharan-carpet-of-t… …. the Messak Settafet is a huge outcrop of sandstone in the middle of the Sahara desert and stone tools litter the entire landscape, averaging 75 per square metre, or 75 million in a square kilometre – which is pretty mind boggling. It goes a long way to appreciate those early to mid 20th century archaeology reports on the Palaeolithic era – with their emphasis on the Sahara and the Acheulian stone tool repertoire.
These tools have been accumulating over hundreds of thousands of years (orthodox chronology) and go all the way back to Homo Erectus. The Massek sandstone, now surrounded by the sand seas of Libya, were a quality rock that was easy to crack and split and generally exploit as a resource. Human activity on the Massek has been prolonged – no wonder there are so many tools – and debitage from making tools. It was an oasis of exploitation in a wider landscape.