OUR FACE FROM FISH TO MAN 



equipment and by profoundly changing what was 

 left of their original heritage. The earliest known 

 vertebrates (or more properly, chordates) are in- 

 dubitably far nearer to us in geologic time and in 

 the ground-plan of their whole organization than 

 they were to the first living creatures; even their 

 faces reveal them, as we shall presently see, as 

 early kinsfolk of ours; the real beginnings of our 

 facial type are either hidden in still unexplored 

 rocks of pre-Silurian ages or wiped out forever by 

 the destructive forces of erosion. From the view- 

 point of earth history as a whole, even the earliest 

 vertebrates of Silurian times (Fig. 4) rank among 

 the younger children of life, yet from the viewpoint 

 of mankind their antiquity is at first inconceivably 

 vast, since according to all recent geological in- 

 quiry, it must be reckoned in hundreds of millions 

 of years. 



The recent monographic researches of Kiser and 

 especially of Stensio upon the amazingly well 

 preserved ostracoderms of the Silurian and Devo- 

 nian ages of Norway and of Spitzbergen have defi- 

 nitely shown that these curious forms are more or 

 less directly ancestral to the hagfishes and lam- 

 preys of the present day, which comparative 



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