114 



LAMARCK, HIS LIFE AND WORK 



tains, since they have been deposited there at very 

 different epochs. But they may often be found mixed 

 together, because the movements of the water, the 

 currents, submarine volcanoes, etc., have overturned 

 the beds, yet some regular deposits in water always 

 tranquil would be left in quite distant beds . . . 

 Every dry part of the earth's surface, when the pres- 

 ence or the abundance of marine fossils prove that 

 formerly the sea has remained in that place, has 

 necessarily twice received, for a single incursion of the 

 sea, littoral shells, and once deep-sea shells, in three 

 different deposits — this will not be disputed. But as 

 such an incursion of the sea can only be accomplished 

 by a period of immense duration, it follows that the 

 littoral shells deposited at the first sojourn of the 

 edge of the sea, and constituting the first deposit, 

 have been destroyed — that is to say, have not been 

 preserved to the present time ; while the deep-water 

 shells form the second deposit, and there the littoral 

 shells of the third deposit are, in fact, the only ones 

 which now exist, and which constitute the fossils that 

 we see." 



He again asserts that these deposits could not 

 be the result of any sudden catastrophe, because of 

 the necessarily long sojourn of the sea to account for 

 the extensive beds of fossil shells, the remains of 

 " infinitely multiplied generations of shelled animals 

 which have lived in this place, and have there succes- 

 sively deposited their debris." He therefore supposes 

 that these remains, " continually heaped up, have 

 formed these shell banks, become fossilized after the 

 lapse of considerable time, and in which it is often 

 possible to distinguish different beds." He then con- 

 tinues his line of anti-catastrophic reasoning, and we 

 must remember that in his time facts in biology and 



