In recent years the Water Resources Branch of the United States Geological Surrey has given considerable attention to the relation of ground‐water to stream‐flow. One locality in which this relation is being studied is about 13 miles from Washington, near Colesvllle, Maryland, where a Kinnison float‐gage is being maintained in a well In connection with the operation of a gaging‐station on the Northwest Branch of the Anacostia River. The well is opposite the gaging‐station, on a gentle slope about one. fifth of a mile from the stream, where the land‐surface ia about 20 feet above the bed of the stream. The well is an abandoned dug well 20 feet deep and is lined with loose stone and presumably admits water freely. The fluctuations of the water‐level in the well are believed to afford a fairly close index of fluctuations in the water‐table at the well‐site and may be typical of the fluctuations that occur in a large part of the area drained by the Northwest Branch above the gaging‐station, consisting of about 21 square miles of gently rolling farm‐land. During the period of the observations herein considered the water‐level in the well ranged from 10 to 16 feet below the ground‐surface at the well and from 10 to 4 feet above the bed of the stream.
