Plate 



No. 



ILLUSTRATIONS 



PLATES. 



1. Tidal sand-waves in the estuary of the River Dovey . Frontispiece 



Page 



2. Aeolian sand-waves near H el wan . . . -33 



3. Aeolian sand-waves with undulating crests (top) . . 43 

 Transverse ridges with longitudinal projections (bottom) . 43 



4. The pits termed fuljes (top) . . . . -47 

 The hillocks termed barchans (bottom) . . . -47 



5. Accumulation of blown sand caused by a fence of reeds 



near Helwan (top) . . . . . -55 



Accumulation of blown sand caused by marram grass at 



Aberdovey (bottom) . . . . -55 



6. Sand-dune with crest reversed by wind (top) . . -59 

 On the slope of a sand-dune having water at its foot (bottom) 59 



7. Pyramidal summit of sand-dune at Ismailia(sand on lee side 



in act of slipping) . . . . . -63 



8. Sand-dune encroaching on a plantation at Ismailia (top) . 67 

 On the top of an encroaching sand-dune at Ismailia (bottom) 67 



9. Sand grains from the cliff of a sand-dune at Ismailia 



(magnified) . . . . . . -71 



10. Aeolian sand-ripples at Southbourne (top) . . -77 

 Aeolian sand-ripples at Southbourne, in which the sorting of 



grains is indicated (bottom) . . . -77 



11. Aeolian sand-ripples at Southbourne, in which the sand 



grains have been much sorted (top) . . -85 



AeoHan sand-ripples at Ismailia, to leeward of a sand-dune 



where there is an upward current of air (bottom) . 85 



12. Drifting waves of dry snow near Montreal (temperature 



minus 8° Fahrenheit) . . . . -99 



23 



