990 



SCIENCE. 



[N. S. Vol. XII. No. 313. 



tory,'* this paper having been prepared and 

 presented at the request of the sectional 

 committee preliminary to the visit of the 

 members of Section E and of the Asso- 

 ciation at large to the American Museum 

 on Tuesday evening. 



Mr. F. H. Newell, in his paper on 

 ' Hydrographic Surveys in New York,' de- 

 scribed the objects and methods of this 

 work as now carried on by the United States 

 Geological Survey. One of the primary 

 reasons urged for preserving the forests 

 is the beneficial influence which they have 

 upon the flow of the streams. The belief is 

 widespread that the forest-cover conserves 

 the waters, prevents floods, to a certain ex- 

 tent, and tends to increase summer flow, 

 and that the cutting off of the forests has 

 resulted in an increase of spring floods and 

 in diminished flow during the summer 

 droughts. All admit these influences, j'et 

 it has been extremel}' difBcult to define the 

 degree to which they are operative and to 

 obtain convincing data for the support of 

 conclusions. 



It is important to know within reason- 

 able limits to what extent the forests 

 and other conditions influence the flow of 

 streams ; and the Division of Hydrogra- 

 phy of the United States Geological Survey, 

 cooperating with the Division of Forestry 

 of the Department of Agriculture, is en- 

 deavoring to bring together facts upon 

 which an answer to this important ques- 

 tion can be based. The first step is to 

 learn of the fluctuations of various rivers 

 in different parts of the United States, to 

 ascertain their regimen and to compai'e 

 this with the cultural conditions of their 

 drainage areas. To obtain these facts it is 

 necessary that careful examinations be car- 

 ried on through several years, so as to in- 

 clude periods of drought as well as those of 

 excessive precipitation. For this purpose 

 typical streams in various parts of the 



* Published in Science. 



United States have been selected and sta- 

 tions have been established, at which the 

 flow of the rivers is systematically meas- 

 ured. These river stations in many States, 

 both east and west, cover almost every 

 range of climatic condition from humid to 

 arid. In the State of New York about 20 

 river stations are now being maintained, 

 most of these being located on streams 

 coming from the Adirondacks to form the 

 upper Hudson, the Mohawk or the Black 

 River. Cooperation in this work is main- 

 tained with the State Engineer and Sur- 

 veyor, and also with the Forest, Fish and 

 Game Commission recently appointed. 



Diagrams showing the fluctuations of the 

 streams from day to day throughout the 

 year are prepared from the results of meas- 

 urements, enabling a person to comprehend 

 at a glance the great variation in volume 

 of the streams under natural conditions. 

 Knowing the changes which follow causes 

 beyond the control of man, it should be 

 possible to ascertain the relative importance 

 of the fluctuations which result from arti- 

 ficial or controllable causes. It may re- 

 quire observations extending over a con- 

 siderable length of time before we can 

 definitely discriminate between effects pro- 

 duced by changes in the forest conditions ; 

 but however long the time or great the ex- 

 pense, it is of the first importance to ascer- 

 tain these facts. 



Mr. W J McGee's paper on the ' Occur- 

 rence of the Pensauken (?) Formation ' 

 within the limits of the city of Washing- 

 ton, brought out the following salient fea- 

 tures: The commonly recognized geologic 

 series in Washington and vicinity com- 

 prises, in descending order, (1) Later (low 

 level, or fluvial) Columbia ; (2) Earlier 

 (high level, or interfluvial) Columbia; 

 (3) Lafayette; (4) Chesapeake; (5) Pa- 

 munkey ; and (6) Potomac. In a few lo- 

 calities, especially in the deep cutting in 

 the 200-foot terrace at the head of Six- 



