In some papers which have lately appeared in the Geological Magazine, I have endeavoured to show that the Ural Mountains, and also the great masses of high land in Eastern Asia from the Altai to the Himalayas, are of very recent geological origin, and that it was probably their rapid elevation which caused the great diluvial movement of which traces are to be found all over the Siberian plains. I now wish to call attention to some of the evidence which points to the American Cordillera being also a very recent geological feature, and dating from the same period of cataclysmic revolution which closed the Mammoth age.

It is a curious fact that one name, America, connotes both of the great continents hung together by the isthmus of Panama. The cause of this is of course purely historical, and yet it coincides with a great physical fact, namely, their essential unity in more than one respect. The generic unity of the old inhabitants of both continents is a peculiar fact in ethnography; but the unity is even more remarkable in this, that the vertebral column which runs north and south through the two Americas is essentially one backbone.