.Science, Geology and Physics 



the author on the rate of recession of the Falls. The same abstract is 1907 

 published in the Geological magazine, decade 5, 1907. 4:440-441. Spencer 



Spencer, Joseph William Winthrop. Recession of the Niagara 

 Falls. (Geol. mag. Decade 5. 1907. 4:440-441.) 



1908 



Faris, R. L. Digest of paper by Spencer on " Soundings under 1908 

 Niagara Falls and in gorge " later published in his " Evolution of Falls Farit 

 of Niagara." (Sci., Apr. 10, 1908. 27:587-589.) 



Gilbert, Grove Karl. Evolution of Niagara Falls. Review of 1908 

 Spencer's book. (Sci., July 31, 1908. 28:148-151.) Gilbert 



Gregory, J. W. Niagara as a geological chronometer. (Nature, 1908 



Nov. 5, 1908. 79:11-12.) Gregory 



A sympathetic review of Spencer's monograph on " The Falls of 

 Niagara: their evolution and varying relations to the Great Lakes." 



Hulbert, Archer Butler. The Niagara River. N. Y. and 1908 

 Lond. : G. P. Putnam's Sons. 1 908. Hulbert 



In the endeavour to gather into one volume a proper descrip- 

 tion of the various interests that centre in and around the Niagara 

 River the author of this book felt very sincerely the difficulties 

 of the task before him. As the geologic wonder of a continent 

 and the commercial marvel of the present century, the Niagara 

 River is one of the most remarkable streams in the world. In 

 historic interest, too, it takes rank with any American river. — 

 Preface. 



Chapter III 

 The Birth of Niagara 



Geologic time presents to the scientist one of the most dim- 

 cult problems with which he has to deal. When the different 

 divisions into which he would divide the ages are numbered by 

 thousands and even millions of years, the human mind is appalled 

 at the prospect; and when the calculations of different geologists 

 vary by hundreds of thousands of years, the lay mind cannot 

 help growing somewhat credulous, and at times be tempted to 

 discard the whole mass of scientific data relating to the subject. 

 y 43 673 



