BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 28, pp. 905-916 December 14, 1917 



DIAGNOSTIC CHAEACTEEISTICS OF MARINE CLASTICS ^ 



BY E. M. KINDLE 



(Prese7ited before the Society December 29, 1916) 



CONTENTS 



Page 



[iitrodiiction 905 



Relative rates of deposition in saline and in fresh water 906 



Structures developed in marine beds 909 



Effect of desiccation on saline and on f resli-water muds 910 



Ripple-mark , 913 



Summary 916 



Introduction 



"A more accurate and quantitative knowledge of tliat eartli history 

 which is now being recorded is needed in order to obtain in turn a more 

 accurate knowledge of the past/^ This statement, quoted from Professor 

 Barrell/ is important enough to be repeated and put in the form of an 

 admonition to geologists which might be framed thus : "Know well the 

 present before crossing the threshold of the past.'^ I have attempted in 

 recent years, so far as circumstances and official duties would permit, to 

 carr}^ out in some measure the spirit of this admonition. Somen:)f the 

 scraps of information which I have gathered while trying to understand 

 present-day processes in geology have a bearing on the subject which has 

 been assigned me. These will be offered for your consideration frankly 

 as fragmentary materials and suggestions for the precise definition of the 

 criteria of marine elastics which will be written some time in the future. 



Any discussion of tlie criteria which characterize marine elastics may 

 well begin by noting the great contrast in composition which distin- 

 guishes marine from fluvial and lacustrine waters. This difference con- 



1 The third of a series of papers composing a "Symposium on the Interpretation of 

 Sedimentary Rocks." 



Manuscript received by the Secretary of the Society April 10, 1017. 

 Published with the permission of the Director of the Canadian Geological Survey. 

 - .1. Barrel! : Criteria for the recognition of ancient delta deposits. Bull. Geol. Soc. 

 Am., vol. 23, 1912, p. 446. 



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