Sea in culture of barbarian invaders and knowledge of geography took a backward step. In the seventh century, Isidore of Seville produced a "wheel map" in which Asia, Africa and Europe were arranged like segments in an orange, separated by the "Mare Mediterranean", "Nilus" and "Tanais" and surrounded by "Oceanus". It was not until the fifteenth century that Ptolemy's maps were used again and Henry the Navigator of Portugal initiated ocean exploration and maritime research. Encouraged by him, Portuguese navigators explored, mapped and charted the west coast of Africa and the Eastern Atlantic and this knowledge prepared the way for the great voyages
Turgai Sea separated Europe from Asia." The division of the Eurasian landmass by the Turgai Sea had the effect of isolating animal populations. Perhaps best known to laypeople were the horned dinosaurs called Ceratopsia of the Cretaceous Period, which were restricted to Asia and western North America (which were connected for much of this era). The existence of the Turgai Sea also restricted various freshwater fish and amphibians. The Turgai Sea derives its name from a region of modern-day Kazakhstan, with its Turgai River and Turgai Valley. Turgai Sea The Turgai (or Turgay) Sea or Turgai Strait, also known as the West