122 LAMARCK, HIS LIFE AND WORIC 



matter, he thinks he can, without great error, consider 

 the mean rate as 324 mm. (i foot) a century. As a 

 concrete example it has been observed, he says, that 

 one river valley has risen a foot higher in the space of 

 eleven years. 



Passing by his speculations on the displacement of 

 the poles of the earth, and on the elevations of the 

 equatorial regions, which will dispense with the neces- 

 sity of considering the earth as originally in a liquid 

 condition, he allows that " the terrestrial globe is not 

 at all a body entirely and truly solid, but that it is 

 a combination (reunion) of bodies more or less solid, 

 displaceable in their mass or in their separate parts, 

 and among which there is a great number which 

 undergo continual changes in condition." 



It was, of course, too early in the history of geology 

 for Lamarck to seize hold of the fact, now so well 

 known, that the highest mountain ranges, as the Alps, 

 Pyrenees, the Caucasus, Atlas ranges, and the Moun- 

 tains of the Moon (he does not mention the Hima- 

 layas) are the youngest, and that the lowest mountains, 

 especially those in the more northern parts of the con- 

 tinents, are but the roots or remains of what were 

 originally lofty mountain ranges. His idea, on the 

 contrary, was, that the high mountain chains above 

 mentioned were the remains of ancient equatorial 

 elevations, which the fresh waters, for an enormous 

 multitude of ages, were in the process of progressively 

 eroding and wearing down. 



What he says of the formation of coal is note- 

 worthy : 



" Wherever there are masses of fossil wood buried 



