“…Aeromagnetic maps suggest that the volcanic rocks pinch out about at the latitude of Lathrop Wells and therefore that alluvial deposits constitute most or all of the cover in the Amargosa Desert. This seems evident at the coarse high-altitude scale of the State aeromagnetic map (1:500,000, Zietz and others, 1977), of which the relevant part is presented here, enlarged, as figure 7 and apparently confirmed by low-altitude surveys (Greenhaus and Zablocki, 1982, fig. 4; Kane and Bracken, 1983).…”