HYDROLOGY. 
87 
Arrangements have also been made for cooperation of both geologists 
and topographers in furnishing information of new water developments 
and such facts relating to the occurrence of underground waters as 
come to their attention. 
Fig. 5. — Map showing progress of work on underground waters in eastern half of United Stales 
in 1903-4. 
During the last few years hydrologic work has been done, either di- 
rectly in the held or through cooperation with State officials or by corre- 
spondence, in practically every State and Territory. Among the more 
important investigations under way ma}^ be enumerated the following: 
In the eastern section, geology and water resources of Long Island, 
