In May 1965, a comprehensive set of 3.5‐kHz propagation‐loss measurements was obtained under downward‐refraction conditions in an area 40 NM south of Montauk, Long Island, New York. A technique for measuring bottom loss in shallow water, derived by taking advantage of the downward‐refraction conditions, was applied to the test area. A bottom‐loss value of 1.3 dB per bounce was inferred from the measurements and was shown to compare favorably with theoretical loss values generated using sediment information for the test area. As a result of that agreement, a computer model based on ray theory and bottom‐impedance considerations was developed to describe shallow‐water propagation in the test area (at least under downward‐refraction conditions). To validate this model and further test the validity of the bottom‐loss measurement, some additional measurements were conducted in the same test area during May 1967. This paper presents the propagation‐loss results collected during the May 1967 measurements and compares them with those predicted by the model developed from the earlier set of measurements.