[On the Origin of Species by Charles Darwin]@TWC D-Link bookOn the Origin of Species CHAPTER XI 2/42
In the older tertiary beds a few living shells may still be found in the midst of a multitude of extinct forms.
Falconer has given a striking instance of a similar fact, for an existing crocodile is associated with many lost mammals and reptiles in the sub-Himalayan deposits.
The Silurian Lingula differs but little from the living species of this genus; whereas most of the other Silurian Molluscs and all the Crustaceans have changed greatly.
The productions of the land seem to have changed at a quicker rate than those of the sea, of which a striking instance has been observed in Switzerland. There is some reason to believe that organisms high in the scale, change more quickly than those that are low: though there are exceptions to this rule.
The amount of organic change, as Pictet has remarked, is not the same in each successive so-called formation.
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