Measurements made between the Galapagos Islands and Ecuador in June and October 1967 revealed the existence of a subsurface high-salinity core aligned beneath the southern edge of the Equatorial Front….
Stevenson, Merritt R., and Bruce A. Taft. 1971. "New evidence of the Equatorial Undercurrent east of the Galapagos Islands." Journal of Marine Research 29, (2). https://elischolar.library.yale.edu/journal_of_marine_research/1205