This paper presents a description of the Gulf Stream system between Cape Hatteras and 63° W. Long. and gives a qualitative analysis of the water masses in the surface layer on the basis of observations taken from November 15 to December 6, 1948. The edge of the Stream was explored for 1,050 miles of its length. The meanderings of the Stream and its tendency to develop large eddies are demonstrated. Of special note was the 90° change in direction of the mean axis of a 150-mile segment of the Stream within a period of two weeks....