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PREFACE, 





conflict with generally accepted theories. The only course for me to pursue was, 

 to examine with care the evidence offered, and, if I could find no flaw in it, to make 

 it public. I may be permitted, in this connection, to allude to the circumstance that 

 nearly all those who refuse to accept my conclusions as to the great antiquity of man 

 in California, do so on the ground that the Calaveras skull was not taken from its 

 bed by the hand of a scientific man. In so doing, they not only ignore the evidence 

 presented by the skull itself, which is positively a fossil, and was chiselled out of its 

 gravelly matrix in the presence of several eminent authorities, but they also reject 

 the very full testimony from other quarters, some of which comes from men of educa- 

 tion, and even of professional education. The body of this other evidence is so great 

 that it does not appear to me that it would be materially weakened by dropping that 

 furnished by the Calaveras skull itself. 



At the time of beginning the present volume, it was my intention to include in it some 

 account of the glacial phenomena and surface geology of the Pacific Coast, as being- 

 subjects closely connected with the occurrence of the gravels. After some further con- 

 sideration, finding that a volume which should contain this additional matter would 

 be inconveniently bulky, I thought it best to divide the work, and to issue the glacial 



and surface geology separately. This has been done, and the first part of the " Climatic 

 Changes of Later Geological Times : A Discussion based on Observations made in the 

 Cordilleras of North America," will appear at the same time with the concluding portion 

 of the present work. The part first issued contains a pretty full account of the glacial 

 phenomena of the region of the Cordilleras, and a brief recapitulation of those facts which 

 prove, beyond possibility of doubt, that during the later geological periods a gradual 

 desiccation of the earth's surface has been going on, and, as there is good reason to 

 believe, is still continuing. The concluding portion of the " Climatic Changes " will be 



issued during the coming winter: it will contain a discussion of the facts set forth 

 in the preceding two chapters and in the gravel volume, showing a gradual diminution 

 in the amount of precipitation, as having been begun during a previous geological 

 epoch and as still continuing, while, in. certain regions, large areas have been covered 

 by ice where none now remains. The endeavor will be made to trace the connection 

 of these facts, and to show that they are manifestations of one great general cause, which 

 has been in operation during an indefinite period, and is likely to continue to operate in 

 the future. 



J. D. WHITNEY 



Cambridge, Mass., Oct. 1, 1880. 





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