In the course of the younger Tertiary, a sea spread over the territory of Europe up to the Black and Caspian seas, whose outcrop, the Eastern Paratethys, connected with the Indian Ocean approximately in the area of Iran. Together with the Mediterranean Sea, it formed an important link between the Indian Ocean and the Atlantic and, thanks to the flow of warm water masses in subtropical to equatorial regions, it ensured the maintenance of relatively high air temperatures over the continent.