submarine depression in the Atlantic Ocean that rises to meet the submerged Mid-Atlantic Ocean Ridge to the west and the western African coast to the east. With the contiguous Canary Basin (north), it forms an arc that swings around the western coast of Africa west and southwest of the Cape Verde islands. Though the greater part of the Atlantic Ocean floor is covered by oceanic oozes, in the Cape Verde Basin, which has an average depth of more than 23,600 feet (7,200 m) below sea level, the ooze is replaced by red clay. Here the waters are warmer and saltier and are joined by cooler waters from the Sierra Leone Basin on the south. The Canary Current, flowing southward into the basin, blends with and is warmed by the Atlantic Equatorial Countercurrent in the west and the Guinea Current to the south.