5. That extension of the ice-cap is admitted by most of the geologists who have specially studied the glacial age. The Russian Geological Survey already has taken this view as regards Russia, and most German specialists maintain it as regards Germany. The glaciation of most of the central plateau of France will not fail to be recognized by the French geologists, when they pay more attention to the glacial deposits altogether. 6. Prehistoric Times, pp. 232 and 242. 7. Bachofen, Das Mutterrecht, Stuttgart, 1861; Lewis H. Morgan, Ancient Society, or Researches in the Lines of Human Progress from Savagery through Barbarism to Civilization, New York, 1877; J.F. MacLennan, Studies in Ancient History, 1st series, new edition, 1886; 2nd series, 1896; L. Fison and A.W. Howitt, Kamilaroi and Kurnai, Melbourne. These four writers--as has been very truly remarked by Giraud Teulon,--starting from different facts and different general ideas, and following different methods, have come to the same conclusion. To Bachofen we owe the notion of the maternal family and the maternal succession; to Morgan--the system of kinship, Malayan and Turanian, and a highly gifted sketch of the main phases of human evolution; to MacLennan--the law of exogeny; and to Fison and Howitt--the cuadro, or scheme, of the conjugal societies in Australia. All four end in establishing the same fact of the tribal origin of the family. When Bachofen first drew attention to the maternal family, in his epoch-making work, and Morgan described the clan-organization,--both concurring to the almost general extension of these forms and maintaining that the marriage laws lie at the very basis of the consecutive steps of human evolution, they were accused of exaggeration. However, the most careful researches prosecuted since, by a phalanx of students of ancient law, have proved that all races of mankind bear traces of having passed through similar stages of development of marriage laws, such as we now see in force among certain savages. See the works of Post, Dargun, Kovalevsky, Lubbock, and their numerous followers: Lippert, Mucke, etc. 8. None 9. For the Semites and the Aryans, see especially Prof. Maxim Kovalevsky's Primitive Law (in Russian), Moscow, 1886 and 1887. Also his Lectures delivered at Stockholm (Tableau des origines et de l'evolution de la famille et de la propriete, Stockholm, 1890), which represents an admirable review of the whole question. Cf. also A. Post, Die Geschlechtsgenossenschaft der Urzeit, Oldenburg 1875.