PALEONTOLOGY 443 



PALEONTOLOGY. 



Case, E. C, University of Michigan, Ann Arbor, Michigan. Study of the 

 vertebrate fauna and palceogeography of North America in the Permian 

 'period, with especial reference to world relations. (For previous reports see 

 Year Books Nos. 2, 4, 8-19.) 



Work under this grant was begun with the idea of establishing by a 

 concrete illustration the necessity for recognition by all workers in 

 palaeobiology that an enumeration of the morphological characters 

 of an organism and any proposals for taxonomic or phyletic arrange- 

 ments, based on morphological characters alone, are inadequate to 

 serve the purposes of palseontological inquiries in the present stage of 

 scientific knowledge. 



Palseogeography has been regarded for too long and by too many men 

 as a record of the limits of bodies of land and water during definite 

 periods of geological time. Maps based upon the recorded occurrence 

 of strata, correlated by methods which have been under discussion 

 for a long period, and the accuracy of which is open to serious question, 

 are of greater or less accuracy as determined by the amount and clarity 

 of the data and the wisdom of the producer. They have been an 

 invaluable aid or have resulted in material advance of knowledge 

 because of the criticism applied to them. 



The delimitation of areas of aggradation or degradation is, how- 

 ever, but a small element in the answer to any palseogeographic prob- 

 lem. Such limits are the result of diastrophism of greater or less 

 degree and serve their main purpose in helping to isolate definite 

 periods of development in the earth's history. 



Palseogeography has a far wider field and can only be defined in the 

 terms of neogeography. However different the concepts of the con- 

 tent of this subject may be, and however widely the different and 

 specialized branches of the subject may diverge from each other in 

 content and method of approach, the central idea remains unchanged. 

 Diversely expressed by many writers, the fundamental idea is that 

 "geography treats of the response of the living organism to its environ- 

 ment." 



The application of this principal idea to palseogeography introduces 

 elements of the first order which immensely complicate the subject. 

 The neogeographer may observe the organism in its actual environ- 

 ment; the palseogeographer must first restore the environment and the 

 organisms as perfectly as may be, by all the resources of several 

 branches of science, before the question of responses within the complex 

 can be taken up. 



A tentative plan of attack and method of procedure has been out- 

 lined in Chapter I of Publication 283 of the Carnegie Institution of 

 Washington, and a concrete illustration of the use of the method given 



