540 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1931 



sifting of the evidence provided by the associated mammals subse- 

 quently led the geologists to decide that the real age was Lower 

 Quaternary (very early Pleistocene). Professor Schlosser in 1903 

 and all subsequent writers for the next quarter of a century believed 

 that fossils found in deposits earlier than the loess of the Chili 

 plain were Pliocene. But investigations during the season 1927-28, 

 fully recorded in the exhaustive report published by Pere Teilhard 

 de Chardin and Dr. C. C. Young (Bull. Geol. Soc. China, 1929, p. 

 173), established the age of the fossils as Early Pleistocene. 



Dr. Davidson Black claimed that the morphology and the pro- 

 portions of the tooth left no doubt either of its human origin or of 

 the fact that it is generically distinct from all other known human 

 types. He came to the conclusion that its original possessor was a 

 child corresponding in age to that attained by modern children at 

 8 years, and presumed that it was derived from the same jaw as the 

 lower premolar tooth whose discovery was reported in 1926 by 

 Doctor Zdansky. 



In 1903 Professor Schlosser had emphasized the fact that while 

 the tooth he was describing on that occasion differed from those of 

 other known human and simian remains, morphologically it was 

 essentially human in type, but revealed certain remarkable points of 

 similarity to one of the fossil apes from the Siwalik Hills. The tooth 

 found in 1927, like that of 1903, was partly embedded in a stony 

 matrix which, in addition to the condition of mineralization of the 

 tooth itself, corroborated the extreme age of the specimen. 



In a monograph published in 1927 (Palaeontologia Sinica, ser. D, 

 vol. 7) Dr. Davidson Black gave a detailed description of the tooth 

 found by Doctor Bohlin in that year. He called attention to its dis- 

 tinctive characters, and contrasted it with a series of primitive hu- 

 man and simian teeth. He provides ample justification for his action 

 in creating a new genus and species of the human family. He shows 

 how every character of the tooth, the form and proportions of the 

 crown, the peculiarities of the roots and the size and form of the 

 pulp cavity all agree in conferring upon Sinanthrofus a distinctive 

 position intermediate between man and ape. Moreover, he shows 

 how generalized are the characters of the tooth, so that it enables us 

 to understand how the peculiarities revealed in the later types of the 

 human family have been derived from this extremely primitive type 

 by differentiation of some of the potentialities so clearly manifest 

 in this interesting tooth. He showed also with great clearness how 

 the pattern of the crown showed a distinct likeness to that revealed 

 in the fossil ape DryopithectLS. 



In spite of the very thorough and complete demonstration of the 

 fact that the tooth of Sinanthropus was of early Pleistocene age and 



