Desert regions of the earth, [13], [149-155];

as observatory sites, [12], [13];

help explain Mars, [16], [17], [156];

color of, [149], [151];

compared with color of Mars, [150], [163];

vegetation in, [150];

position of, [153], [154];

due to winds, [154].

Desertism, [16], [89], [153-158].

Deserts (see Reddish-ochre regions).