Editing Simpson Desert (section)

===Morphology===
[[File:PIA00115 Earth (Simpson Desert, Central Australia).jpg|thumb|upright|Simpson Desert visible dune lines and [[Lake Eyre]] at bottom left]]
The sand ridges have a trend of SSE-NNW and continue parallel for great distances.  This pattern is seen throughout the [[deserts of Australia]].  Some of the ridges continue unbroken for up to 200&nbsp;km.  The height and the spacing between the ridges are directly related.  Where five to six ridges occur in 1&nbsp;km, the dune height is around 15 m, but when only one or two ridges occur in 1&nbsp;km, the height jumps to 35–38 m.<ref name=Twidale/> In cross section, the lee side is the eastern slope with an incline of 34-38°, while the [[Ripple marks#Definitions|stoss side]] is the western slope with an incline of only 10-20°.  In cross section, the cross beds are planar with [[foreset bed|foresets]] alternating between east and west.  The foresets have incline angles of 10-30°.<ref name=Twidale/>