BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Vol. 21, pp. 625-662, PLS. 43-47 NOVEMBER 15, 1910 



CRITEEIA FOE THE RECOGKITIOISr OF THE VARIOUS 

 TYPES OF SAND GRAINS^ 



BY WILLIAM H. SHEEZER 



(Presented before the- Society December 29, 1909) 



CONTENTS 



Page 



The thesis stated 1 625 



Classification of sand, grains 626 



Glacial sand type 628 



Volcanic sand type 629 



Residual sand type 630 



Aqueous sand types 632 



^olian sand types 638 



Organic sand type 643 



Concentration sand type 647 



Application to the Sylvania sandstone 650 



Explanation of plates 657 



The Thesis Stated 



From the phj^sical characteristics and composition of sand grains is it 

 possible to decipher their origin and geological history? This is the 

 question which the writer set himself the task of answering while endeav- 

 oring, conjointly with Prof. A. W. Graban, to determine the origin of a 

 certain Silurian sandrock — the Sylvania^ known in outcrop and borings 

 about the western end of Lake Erie. It may be answered that typical 

 assemblages of the various varieties of sand grains do reveal their own 

 geological history, and that confirmation of this history may be obtained 

 often from a detailed study of the beds in which these grains occur. 

 Concerning the origin of the material from which the grains were carved 

 one may speak less confidently, but with all the obtainable data at hand 

 it seems possible that here, too, a definite answer may be found for each 

 particular deposit. In his presidential address before the Geological 



1 Published by permission of the State Geologist of Michigan, Prof. R. C. Allen. 

 Manuscript received by the Secretary of the Society February 9, 1910. 



(625) 



