266 ANNALS NEW YORK ACADEMY OF SCIENCES 



interest in the subject relates to the mechanisms by means of which this 

 independence of the environment is secured. The study of the effects 

 of the environment may be taken up in terms of the changes in internal 

 conditions. If the environment really does affect these internal con- 

 ditions, we have the possibility that the environment is one cause of 

 variations. The questions of adaptation, the struggle for existence, the 

 survival of the fittest and geographical distribution may all be approached 

 from this point of view. 



The paper was discussed by Dr. E. L. Scott. 



The Section then adjourned. 



William K. Geegoey^ 



Secretary. 



SECTIOJSr OF GEOLOGY AKD MINEEALOGY 

 20 Maech, 1916 



Section met at 8 :15 p. m.^ Vice-President Douglas W. Johnson pre- 

 siding. The minutes of the last meeting of the Section were read and 

 approved. 



The following program was presented: 



Willis T. Lee, Application of Phtsiogeaphic Methods to the 



COERELATION OF NON-MAEINE EOEMATIOlSrS IN THE 



EocKY Mountains. 



SUMMAEY OF PaPEE 



Dr. Lee described his attempt to work out the sequence of events dur- 

 ing the physiographic evolution which resulted in the stratigraphic and 

 structural relations now observed in the rocks of the Mesozoic age in the 

 mountain region. The ancestors of the present Eocky Mountains were 

 eroded during Triassic and Jurassic time and late in the Jurassic period 

 they were reduced to a peneplain. On this plain were spread out the 

 continental deposits which constitute the La Plata sandstone and its age 

 equivalents. The lower parts of the plains were covered with sea water 

 in the later part of the Jurassic period. In the sea, where the water 

 was suitable for marine organisms, there accumulated the fossiliferous 

 beds which now are called Sundance. However, the sea water found its 

 way landward over the nearly level plain far beyond the places favorable 

 for the life of marine organisms and gathered in shallow bays where, by 

 evaporation, it became unsuitable for habitation. There are beds of 



