Professor Huxley called attention to this subject in a brief address to the London Ethnological Society in 1869. After stating the case, he presented the following queries and suggestions: “The Austro-Columbian fauna, as a whole, therefore, existed antecedently to the glacial epoch. Did man form part of that fauna? To this profoundly interesting question no positive answer can be given; but the discovery of human remains associated with extinct animals in the caves of Brazil, by Lund, lends some color to the supposition. Assuming this supposition to be correct, we should have to look in the human population of America, as in the fauna generally, for an indigenous or Austro-Columbian element, and an immigrant or ‘Arctogeal’ element.” He then suggests that the Esquimaux may now represent the immigrant element, and the old Mexican and South American race that which was indigenous, and that the “Red Indians of North America” may have appeared originally as a mixture of these two races. He adds, very reasonably, “It is easy to suggest such problems as these, but quite impossible, in the present state of our knowledge, to solve them.” WHO WERE THE MOUND-BUILDERS? They were unquestionably American aborigines, and not immigrants from another continent. That appears to me the most reasonable suggestion which assumes that the Mound-Builders came originally from Mexico and Central America. It explains many facts connected with their remains. In the Great Valley their most populous settlements were at the south. Coming from Mexico and Central America, they would begin their settlements on the Gulf coast, and afterward advance gradually up the river to the Ohio Valley. It seems evident that they came by this route; and their remains show that their only connection with the coast was at the south. Their settlements did not reach the coast at any other point.