310 CARNEGIE INSTITUTION OF WASHINGTON. 



tinued growth and well-being of young animals. This discovery was 

 also made, independently and simultaneously, by McCollum and 

 Davis, but it has not yet been learned whether this food factor, now 

 known as the fat-soluble vitamine, is also necessary for the maintenance 

 of mature animals. At the present time it is desirable to have a posi- 

 tive answer to this question, for where milk supplies are restricted it 

 is important to know whether adults can safely substitute other fats 

 for butter. Experiments directed to this end are in progress, but do 

 not yet permit final conclusions. 



PALEONTOLOGY. 



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

 vertebrate fauna and paleogeography of North America in the Permian 

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

 Year Books Nos. 2, 4, 8-16.) 



The manuscript of the first part of the work upon the paleogeography 

 of North America in the late Paleozoic has been completed and sub- 

 mitted to the Carnegie Institution of Washington. This work in- 

 cludes, as a preliminary chapter, a discussion of the elements of a 

 paleogeographic problem. Then follow chapters upon the stratigraphy, 

 paleobotany, climatology, and physiography of North America in the 

 late Paleozoic. A chapter discusses the interpretation of the deposits 

 and other evidence as revealing the environment of vertebrate life. 

 The final chapter is devoted to a discussion of the development and 

 fate of the vertebrate life in relation to its environment. Evidence is 

 given that the gradual uplift of the continent from the east toward 

 the west produced a great migrating climatic change advancing toward 

 the west and involving successively higher geological formations. 

 This climatic change is traced by the peculiarities of the deposits 

 shown to cut obliquely across the stratigraphic series. The conditions 

 produced by the climatic migration are designated as 'Termo-Carbon- 

 iferous conditions" and are recognized as a distinct geological unit 

 independent of any distinct period of time. The correlation of these 

 conditions largely removes the difficulties in understanding the dis- 

 tribution, geographic and stratigraphic, of the late Paleozoic verte- 

 brates. 



It is also shown that the elevation of the western side of the continent 

 of North America in late Paleozoic time terminated the migration of 

 the great climatic change and converted the northern portion of the 

 Basin Province into a region of stagnant seas, in which were deposited 

 the sediments of the Park City formation of northeastern Utah and 

 the equivalent formations of adjacent States. 



