170 



near the crest of an active blowout are constantly being un- 

 dermined, and slide down with the loose sand towards the bot- 

 tom (PI. XVI.). They are not killed directly by this, but are 

 frequently seen alive near the bottom, and in this way are di- 

 rectly available in holding the sand. 



TABLE Vltl. BLOW SAND. 



(Fixation just begun.) 



Sporobolis cryptandrus 

 Chrysopsis camporum 

 Cassia cliaiua'crista 

 Ambrosia psilostachya 

 Moiiarda punctata 

 Euphorbia (ireyeri 

 (iyperus Bushii 

 Paspalum setaceuni 

 Conimeliiia vireinica 



d*d d c d 



d d c d d 



d c a c <• 



c d c d il 



o o o a a 



d o o o o 



o o o a 



o a o o 



o o o o a 



TABLE IX. BLOW-SAND. 



(Nearly tixeti.) 



Sporobolus cryptandrus 

 Chrysopsis camporum 

 Lespedeza capitata 

 Ambrosia psilostachya 

 Cyperus Schweinitzii 

 Monarda punctata 

 Paspalum setaceum 

 Aristida tuberculosa 

 Croton glandulosus 

 Leptilon canadense 



e* e d d e 



d c c d (I 



c c c b a 



b c c b o 



o a a a b 



o a a a a 



o o a o o 



o o o b b 



a () o o o 



o a o o o 



But one other result of the movement of the sand remains 

 to be considered, and that is the effect of the blow-sand on the 



See p. 1.59. 



