BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Vol.32, pp. 333-338 SEPTEMBER 1, 1921 



PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY 



CEITERIA FOE THE DETERMINATION OF THE CLIMATIC 

 ENVIRONMENT OF EXTINCT ANIMALS ^ 



BY E. C. CASE 



{Presented before Ike Paleontological Society Decemher 20, 1920) 



CONTENTS 



Page 



Categories of criteria 333 



Inorganic criteria : Character of sediments 3.34 



Unaltered sediments 335 



Altered sediments .336 



Organic criteria 337 



It is unnecessary for the speaker to apologize for the incompleteness 

 of this summarjr paper, for within the limits of time at his disposal no 

 adequate treatment can be attempted.^ Simpl}' an attempt has been made 

 to set down in coherent form the main points which should be in the mind 

 of every one who is attempting to determine the climatic environment of 

 a fossil form or a group of fossil forms found in any definite bed. 



The criteria suggested in this paper for the determination of the cli- 

 matic environment are not such as might rationally be figured out in an 

 office chair, but are such as have been used by the author in the field and 

 are proven to be practical. Much that should be revealed, from all con- 

 siderations of theory, is commonly hidden, for one reason or another, as 

 every field-worker knows, but certain things can always, or generally, be 

 observed and checked in the field and the laboratory. 



Categories of Criteria 



The criteria for the determination of the climatic environment can 

 easily be placed in two categories, the organic and the inorganic. In the 



' Manuscript received by the Secretary of tlie Society jNlarch ?,, 1021. 

 This paper is one of a series composing a "Symposium on criteria and methods em- 

 ployed in paleontological research." 



- The subject of the interpretation of sedimentary beds has been discussed at some 

 length by the author in Publication Number 28.3 of the Carnegie Institution of Wash- 

 ington, where an attempt has hecn made to indicate how not only the climate but other 

 environmental factors of past life can be made out. 



