This is only a partial answer; meteor falls are pretty common and so their density will be high in flat areas without a lot of flowing water, they're hard to identify without a good eye or at least a sensitive metal detector.
Hopefully a more quantitative source for the areal density of meteor finds can be found. The numbers are there, and if all rocks in the area that Saint-Exupéry describes are light in color, then picking up and checking every dark rock and checking to see if it has indications of burning or melting, this might be possible. Of course if it were this easy to collect them there then it seems others would have gone and collected a lot more. But those people have no incentive to document it since they can (often) be sold for cash apparently.
Note that the meteors shown in the image from the PRI article linked below are not dark but the dearth of dark meteorites found in Antarctica is a different story (1, 2) though there's been a lot of progress since 1986 when the document you link to was published.
According to Arizona State University's Meteorites page Meteorite Locations:
Since there is an estimated one meteorite fall per square kilometer per year, geologically stable desert regions can show significant accumulations of meteorites. Some desert regions have dozens of different meteorites per square kilometer, though they can be difficult to distinguish from normal terrestrial rocks.
PRI's Want to find a meteorite? Antarctica might be the best place to look says:
This winter, Lanza has been a rookie member of the ANSMET (the Antarctic Search for Meteorites) field team. For 40 years, the project has sent teams of scientists to the bottom of the globe to recover meteorites from all over the solar system, including chunks of the moon, comets, even Mars.
On this trip? Lanza and her colleagues recovered a total of 569 meteorites.
“They are just waiting for us to come and find them,” Lanza says. “You can imagine that blue ice ... and then you just look and there's some dark spots on them. And those are rocks and frequently those rocks are from space.”
Meteorites fall to Earth all the time, but Antarctica is a particularly good place to find them.
“We're lucky with Antarctica,” Lanza says. “It's this big white sheet covered in glaciers. And so these meteorites just become embedded in the ice and start flowing with the glacier. And in some places the glacier will run into something — like the mountain range that we were in — the Miller range. It will slow down and then the winds ... will start to remove some of that ice and that acts to concentrate the meteorites in these locations. So we can actually go there and find many more meteorites than you might imagine would fall in a single location.”
Nina Lanza knows space rocks. In her day job as a staff scientist at Los Alamos National Laboratory, she operates the Curiosity Rover’s ChemCam, using a rock-vaporizing laser to analyze the Martian surface.