RECORDS OF MEETINGS OF 1908 461 



mission, and the successive stages in interpretation of results were pointed 

 out. The paper was also illustrated with lantern slides and charts. 



Professor Kemp said in abstract: Within a few years there has been a 

 marked change on the question of the sources and amount of underground 

 Avater. Although as recently as 1900, in the most important discussion of 

 the influence of ground water, all supplies other than meteoric were elimi- 

 nated as of negligible importance, it is now becoming increasingly more 

 probable that some of these supplies are of magmatic origin. There is a 

 tendency to place much more emphasis upon the interpretation of ore bodies 

 in the light of possible influence of magmatic waters. 



To an equal extent the earlier opinions as to the total amount of under- 

 ground water have been modified. It has been customary to express this 

 as a sheet of water over the surface of the globe of so many feet in depth. 

 Delesse, in 1861, estimated it 7500 feet; Schlichter, 1902, 3000 to 3500 feet; 

 Van Hise, 1904, 226 feet; Fuller, 1906, 96 feet. Ground waters of meteoric 

 origin would seem therefore to be of very moderate amount, and the depths 

 to which they penetrate are probably correspondingly reduced. It may 

 readily be believed that their efficiency and universality in minerahzation 

 has been overestimated. 



The Section then adjourned. 



Charles P. Berkey, 



Secretary. 



SECTION OF BIOLOGY. 



February 10, 1908. 



Section met at 8:15 P. M., Vice-President Chapman presiding. 



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



The following program was then offered: 



N. L. Britton, The Genus Ernodea Swartz: a Study of Species 



AND Races. 



Bashford Dean, Accidental Resemblance and its Possible Im- 



portance IN the Origin of Species. 



C. William Beebe, Preliminary Report of Some Recent Experi- 

 ments with Birds in the New York Zoological 

 Park. 



Frank M. Chapman, The Bird's Wing in Flight as Revealed by 



Photography. 



