The acoustical and physical significance of bottom‐simulating seismic reflections (BSR's) remains an observational challenge to geophysical methods. A common depth point (CDP) seismic reflection profile using a 240‐channel, 6000‐m array with a 177‐liter (5‐ to 60‐Hz) source was collected along the continental rise off the eastern U.S. where a BSR reflection is observed along a small portion of the line at about 3200‐m depth. These data provide some velocity estimates in the vicinity of the BSR. The CDP data were transformed to the domain of vertical delay time and horizontal ray parameter for velocity analysis purposes. Even so, the resulting velocity profiles have limited vertical resolution (about 200 m) due to the distribution of interpreted sedimentary reflections used in the vertical delay time velocity analysis. Even with this admittedly low vertical resolution, the velocity above the BSR is at least 2000 m/s in an approximately 200‐m zone, while the predicted velocity based on the extrapolation of regional gradients indicates that normal sediments should have a velocity of about 1850 m/s. A velocity of 2000 m/s suggests on average about a 50% substitution of hydrate in the pore spaces but the actual vertical concentration gradient is not constrained. This velocity anomaly also extends into other areas just above the theoretical phase boundary position, but where there is no detectable BSR. Beneath the BSR, even with the relatively low vertical resolution, a velocity decrease to about 1700 m/s is detected. This low velocity is observed only in zones with a detectable BSR. It is not observed beneath the theoretical phase boundary position elsewhere. This suggests that the origin of the BSR is not a simple boundary between hydrated and nonhydrated, normal sediments below. Initial investigations of amplitudes indicate significant increase in amplitude with offset. Full waveform, offset modeling of the data is underway.