Fig, 4. Temporarily stable dune near Bullenhof, Riga, Russia. The moving- sand of the lee- 

 slope is in progress of being naturally arrested by grasses, (Koeleria glauca and Festuca 

 ovina), herbs, (Artemisia campestris, Hieracium umbellatum f Pulsatilla pratensis and others), 

 and by pines \Pinus sylvestris.) 



PHOTOGRAPH BT KUPFFER. 



