Seismic data are conventionally recorded, processed and displayed in the X-T domain, where X is the source-receiver. offset and T is the two-way traveltime. There are advantages, however, in mapping the same data in a different domain; that of intercept time T and horizontal ray parameter p. Computer programs .written for performing the transformation from X-T to -p were adapted for use with marine data acquired in the western Isles region of Scotland in order to obtain information about the velocity structure in that area. The results obtained are compared with those produced by the more conventional methods of refraction surveying and it is found that the data are of insufficient quality to facilitate a geological interpretation to be made with the -p method alone and that the method is of no use with the poorest quality data. Recourse to the conventional methods is found to be necessary, and the results obtained verify previous results from other work
