Game Parks were an innovation in my childhood. If we wanted to go anywhere, we would get on our horses and ride off, relying on local people to direct us in the right direction.
The Awash River was an oddity in that it never reached the sea but lost itself in the remote area of the Danakil desert. I can remember at some moment in our history of living in Ethiopia, that we tried to find out what happened to it but failed. It just disappeared in the Danakil depression (some of which was below sea level.
I also remember large areas of black rocks (I think some sort of basalt) appearing initially out of areas of grass. If we found an area, we would get off our horses and try to break bits of this black rock off. It was very spiky to grab hold of so we would use pieces of wood to try and break it off very successfully, but I do remember them as being a dull grey on the outside but a shiny black colour on the inside where the dust had not discoloured it. I also remember that it was quite sharp on the edges of the pieces we had broken off, so we had to be careful not to get our fingers damaged by it.
I had a piece of this rock until quite recently, but I think it has gone astray, I do hope it will show up in one of the drawers of my table or desk.