102 



BOTANICAL GAZETTE 



[FEBRUARY 



samples from 



from 



from 



from 



H 



Queensland, 7 to a series from North 

 / to a series of samples from the Pac 



America 



A 



B 



Submerged beach I Finest 



Front beach | Fine 



Middle beach 



Upper beach 



Littoral dune 



Dunes 



Sand field 



Fine 

 Coarse 

 Medium 

 Medium 



C 



Medium 



Medium 



Fine 



Medium 



Fine 



Finest 



Medium 



Fine 



Coarse 



Coarse 



Medium 



Medium 



J) 



Fine 

 Fine 

 Medium 

 Medium 



Fine 

 Fine 



E 



Finest 

 Coarse 

 Coarse 



Grits 

 Medium 



Medium 

 Finest 



Submerged beach 

 Front beach 



Middle beach. . . . 



Upper beach 



Littoral dune. . . . 

 Dunes 



Sand field 



Coarse 



Medium 



Medium 



Coarse 



Medium 



Fine 



G 



H 



I 

 Coarse 



Medium 



Fine 



Fine 



Medium 



Grits 



Medium 



Coarse 



Coarse 



Medium 



Coarse 



Grits 



Fine 



Medium 



Medium 



Fine 



Medium 



Fine 



Finest 







J 



Medium 



Fine 



Fine 

 Medium 



Fine 

 Fine 



samples, secured at 



In each of the above cases the result represents the average of i° 



approximately corresponding places on eac 

 formation. As these data show, the coarsest sand occurs on the upper 

 beach. The material that builds up the littoral as well as the ordinary 

 dunes is usually of the same grade of coarseness. It is only when * 

 analyze the sand from various places on the dunes that difference- 



aDnear. whirVi f»Yrvlo;», +v.« c ** __ _-.* • ___i 1 i j.^pc a.sdi> 



marks 



cussed on previous pages. It will be seen when we describe the vege- 

 tation on the various formations that the coarseness of the sand 

 some cases seems to determine the composition of the plant com- 

 munities. This is easily understood when we consider that the size 

 of the sand particles determines the water-holding capacity of the soil- 



Chemical composition of sand.— The nutritive value of sand^ 



different according to the chemical character of the sand grains. As 



