In 1969, a series of geophysical tracks was run across the Catoche Tongue, a major re-entrant into the Campeche Slope, Gulf of Mexico. Seismic reflection profiles within the tongue reveal no significant structural differences between the scarp bordering this feature and the main Campeche Scarp. Magnetic data, however, show a 200-gamma anomaly associated with the Campeche Scarp, but the scarp within the tongue has little or no anomaly. A knoll at the mouth of the tongue shows a 250-gamma anomaly. This knoll may be a remnant of the scarp base upon which the bordering reef grew. The nontectonic theory of origin proposed for the Catoche Tongue is supported by these new geophysical data.