RETROSPECT 191 



less ally, smiles at, or tolerates, the ravages of puny 

 man. There is good reason to believe that we of the 

 northern hemisphere may be living in the midst of an 

 interglacial epoch, and, if this be so, that even now 

 slowly but relentlessly the hosts of the ice king are being 

 marshalled to dispossess man of his fair heritage in the 

 north. Twice, at least, in the past, our northern states, 

 as well as Europe, have been buried beneath thousands 

 of feet of ice and snow even as is the south pole to-day. 

 Gradually is being assembled the army that will sweep 

 man before it even as it did the mammoth and mastodon 

 in past ages : advancing a few feet this year, retreating 

 a foot or two next season, but never losing all the ground 

 it has gained, the great ice sheet is slowly shaping out of 

 mist and snow the vast fighting machine that will drive 

 man from the populous cities of the north. And who 

 shall say that 100,000 years from now, when the great 

 earth pendulum has swung the other way, some race of 

 supermen, working northwards as the climate changes, 

 may not be investigatiag the site of this museum and 

 reconstructing the habits of the poor, unintelligent 

 inhabitants of what was once New York. 



American Museum of Natural History 

 May 1,1922. 



REFERENCES. 



Examples of the various animals mentioned in this chapter, as 

 well as in the others, will he found in the American Museum of 

 Natural History. Among them may he mentioned a mounted 

 skeleton of Brontosaurus, two of Trachodon {Thespesius) and the 

 remarkable "mummied" specimen showing the texture of the 

 skin. A single skeleton of the great predatory Tyrannosaurus is 

 shown, pending the construction of an addition to the Museum 

 that will provide room for two complete skeletons. 



The historic Warren Mastodon was acquired some years ago 

 and is placed near the skeleton of a mammoth from Indiana. 



