Desert: The L.A. Mag Guide to Geology

The lay of the desert land


An isolated hill, with steep sides and a flat top, it may be the remnants of a mesa, which has a flat top and at least one clifflike side but is broader.



cinder-coneCinder Cone 
The cone-shaped hill forms downwind of a volcanic vent. Lava flying out of the vent solidifies as it hits the air and accumulates in a neat pile.



desert-pavementDesert Pavement 
It’s a surface layer of pebbles packed closely into the hard soil. One theory holds that it develops as wind and rain remove the finer-grained topsoil.



Illustrations by Roger Hall