22 DISCOURSE ON THE REVOLUTIONS OF 



may say, of the history of man, and that which it most imports him 

 to know in relation to himself. 



If we are interested in tracing out the nearly effaced vestiges of the 

 early periods of our species, in so many nations utterly extinct, why 

 should we not seek to discover, in the obscurity which envelopes that 

 infancy of the earth, relics of revolutions long anterior to the existence 

 of all nations ? We admire that power of the human mind, the exercise 

 of which has enabled us to ascertain those motions of the planets 

 which Nature seemed for ever to have held from us. Genius and science 

 have soared beyond the limits of space. Observations, developed by 

 reason, have detected the mechanism of the world. Would it not be 

 some renown for man, in like manner, to penetrate beyond the limits 

 of time, and to discover, by research and reflection, the history of 

 this world, and of a succession of events which preceded the birth of 

 the human race ? 



Astronomers have advanced in science more rapidly than natu- 

 ralists ; and the present state of the theory of the earth somewhat re- 

 sembles that of the period when certain philosophers believed heaven 

 to be formed of polished freestone, and the moon in size like the Pe- 

 loponnesus ; but after Anaxagoras have arisen Copernicus and Kepler, 

 who paved the way for a Newton ; and why should not natural history 

 one day boast also of her Newton ? 



Plan. 



It is the plan and result of my labours on fossil bones which I par- 

 ticularly intend to lay before you in this discourse. I shall also at- 

 tempt to trace a rapid sketch of the means employed down to the 

 present time to discover the history of the revolutions of the globe. 

 The facts which I have been able to arrive at form certainly but a 

 very small portion of those of which doubtlessly this history of anti- 

 quity was composed ; but many of them lead to decisive results, and 

 the severe method which I have exercised in deciding on them gives 

 me reason to believe that they may be received as assured data, and 

 will constitute an epoch in the science. I trust their novelty will be 

 my excuse if I ask for them the undivided attention of my readers. 



My first object will be to show the relation between the history of 

 fossil bones of terrestrial animals and the theory of the earth, and the 

 motives which in this respect give it a peculiar importance. I shall 

 then unfold^the principles of deciding on these bones, or, in other 

 words, of ascertaining a genus and distinguishing a species by a sin- 

 gle fragment of bone — an art on the certainty of which rests that of 

 the whole of my labours. I shall slightly notice new species and ge- 

 nera formerly unknown, which I have discovered by the application 



