Fig. 4. Temporarily stable dune near BuJlenhof, 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 campestriSj Hieracium umbellatum, Pulsatilla pratensis and others), 

 and by pines (Pinus sylvestris.) 



PIIOTOGRAPTI BT KUPFFER. 



