122 LAMARCK, HIS LIFE AND WORK 
matter, he thinks he can, without great error, consider 
the mean rate as 324 mm. (1 foot)a century. Asa 
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 (réunzzon) 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 
