Page "History of Isan" Paragraph 6

Four Homo erectus fossil skull fragments found in northern Thailand's Hat Pudui cave ( Ko Kha District, Lampang Province ) by Thai paleontologists Somsak Pramankij and Vadhana Subhavanin, were in deposits dating from the mid-Pleistocene era, which was before the Khorat Plateau had uplifted from an extensive plain.

Professor Phillip V. Tobias of Johannesburg's University of the Witwatersrand examined the fragments and said: " It seems unavoidable but to conclude that Thailand must have been a highway or crossroads in the movement of hominids — members of the family of man.