10 GENESIS AND DEVELOPMENT 



and under the most different natural conditions. In the present pajjer 

 I propose to deal briefly with some of the mariae sand formations, their 

 origin, development, and classification, so far as it is necessar}' to 

 demonstrate the most fundamental facts of this subject and the principles 

 on which they are based. I also give short comments upon the principal 

 dune districts visited in the course of my studies. 



To Peofessoe Wm. E. Dudley of Leland Stanford Junior University 

 I am greatly indebted for many favors in connection with my work, 

 and I have also to express my acknowledgments to De. Johax Eeiksox^ 

 Karlskrona, Sweden, Dr. K. E, Kdppfee, Eiga, Eussia, De. W. J. 

 Smith, Leeds, England, B. H. Woodwaed, Esq., E. E. G. S'., Perth, 

 Western Australia, C. E. Benbow, Esq., C. E., Sidney, New South 

 Wales, De. L. Cockayne, Christchurch, New Zealand, and various other 

 persons, who have assisted me with information and photographs. 



SAND FORMATIONS IN GENERAL. 



When we consider the factors which have given rise to the formation 

 of sand, the principal ones are the atmospheric and the aqueous agen- 

 cies, which also are the most important in transportation and distribu- 

 tion of the material. It will therefore be convenient to distinguish 

 between the following general classes of sand deposits: 



1. Eolian sand formations. 



2. Neptunian sand formations. 



The term eolian in this connection was to my knowledge first used in 

 1835 by R. J. Nelson^) and it signifies the agency of wind. Eolian 

 deposits exhibit a different composition and structure from the nep- 

 tunian, those sediments which have been buUt up by the water. The 

 transporting power of water being considerably greater than that of 

 wind, it necessarily follows that the material moved by aqueous agencies 

 varies more in size than that which is carried by the wind. We will 

 have ample opportunity to note this difference as we proceed in. our 

 inquiry. 



No rational nomenclature for the different kinds of soil constituents, 

 neither of inorganic nor of organogenetic origin, has yet been agreed 

 upon, and it will thus be necessary to give here the designations which 

 have been used during my observations in the field. 



1) Proceedings of Geological Society of London, Vol. II.. p. 160. 



