CONNECTING AND MISSING LINKS 



sense he is a connection, but he is not a common ancestor. 

 Heidelberg man and his lineal successor, the man of Nean- 

 derthal, constitute the first and last links of another chain 

 whose slow change is unrecorded for three hundred and fifty 

 thousand years. But these forms are evidently not in the 

 line that led to modern man, although the Neanderthal type 

 was yet alive when Man appeared on the European stage, 

 25,000 years ago. What lies back of our own species is 

 still unrevealed, but we are probably out of an unknown 

 though extremely ancient Asiatic stock. That Asia is the 

 birthplace of humanity most authorities now agree, except 

 the few who, because of the primitive character of the 

 African natives and the antiquity that was Egypt, infer an 

 African origin for the higher races. This inference seems 

 unwarranted, for, although the negroes are primitive in 

 most respects, in others they show a higher specialization 

 than either the yellow or the white races. Fossil forms are 

 now coming to light, especially in the Siwalik region of 

 India, which could be ancestral to the great apes, and pos- 

 sibly to man, but one looks for the final solution of this prob- 

 lem farther to the north, in the comparatively unknown 

 Asiatic plateau. 



That there are gaps in our revealed record of the continu- 

 ity of life — gaps due in part to incomplete exploration, in 

 part to natural causes — is manifest; but that the record is 

 sufficient to uphold the principle of continuity is equally 

 manifest. Sedimentary rocks form the repository of this 

 record, and sedimentation is always locally discontinuous 

 because of the wearing down of the earth's surface until the 

 force and carrying power of the streams have well nigh 

 ceased. This wearing down of the land is followed period- 

 ically by its re-elevation through crustal movement, with 

 consequent rejuvenation of the streams, which begin once 



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