LAMARCK'S WORK IN GEOLOGY 115 



geology were feebly grasped, and scientific reasoning 

 or induction was in its infancy. 



" I would again inquire how, in the supposition of 

 a universal catastrophe, there could have been pre- 

 served an infinity of delicate shells which the least 

 shock would break, but of which we now find a great 

 number uninjured among other fossils. How also 

 could it happen that bivalve shells, with which cal- 

 careous rocks and even those changed into a silicious 

 condition are interlarded, should be all still provided 

 with their two valves, as I have stated, if the animals 

 of these shells had not lived in these places ? 



" There is no doubt but that the remains of so 

 many molluscs, that so many shells deposited and 

 consequently changed into fossils, and most of which 

 were totally destroyed before their substance became 

 silicified, furnished a great part of the calcareous 

 matter which we observe on the surface and in the 

 upper beds of the earth. 



" Nevertheless there is in the sea, for the formation 

 of calcareous matter, a cause which is greater than 

 shelled molluscs, which is consequently still more 

 powerful, and to which must be referred ninety-nine 

 hundredths, and indeed more, of the calcareous matter 

 occurring in nature. This cause, so important to 

 consider, is the existence of cor alligenous polyps, which 

 we might therefore call testaceous polyps, because, like 

 the testaceous molluscs, these polyps have the faculty 

 of forming, by a transudation or a continual secretion 

 of their bodies, the stony and calcareous polypidom 

 on which they live. 



" In truth these polyps are animals so small that 

 a single one only forms a minute quantity of calca- 

 reous matter. But in this case what nature does not 

 obtain in any volume or in quantity from any one 

 individual, she simply receives by the number of ani- 

 mals in question, through the ^enormous multiplicity 



