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to accept the conclusion of M. Ehrenberg as probable. It 

 is, moreover, confirmed by the facts already alluded to, of 

 one or two species of recent shells, (Terebratula caput 

 serpentis and T. vitrea,) which are regarded by eminent 

 naturalists as undistiniyuishable from the T. striatula and 

 T. subundata of the chalk. 



We must, therefore, admit, in respect of the living species of 

 these microscopic Foraminifera and Infusoria, an earlier date 

 among the stratified rocks than belongs to nearly every other 

 living type; an interesting conclusion, on which M. Ehrenberg 

 has founded a series of propositions, which are valuable, but 

 less novel than some authors suppose. For it is not only 

 perfectly well established in Geology, that each group of life 

 has its own laws of distribution in the earth, which can only 

 be known by observation, but further, that the Geological 

 range through which fossil species occur is greater in the in- 

 vertebral than in the vertebral tribes ; greater in the Mollusca 

 than in the Crustacea ; and greater in the Zoophyta, to which 

 these fossil Foraminifera, and some at least of the Infusoria, 

 belong, than in any other grade of animal life. 



In accordance with this view, we find in the Mountain 

 Limestone, Zoophyta and Mollusca, which are referrible to 

 existing genera, with Fishes of extinct genera, but no 

 Reptiles ; in the chalk. Reptiles of extinct genera, with 

 Zoophyta and Shells, of which one or two belong even to 

 living species ; and in the marls of Bielbeck, in Yorkshire, 

 thirteen forms of Shells, belonging to species now living, 

 with the extinct Elephant, Rhinoceros, and Lion. 



The subject to which I have called your attention to-day 

 is one which it is difficult to guard from the rash hands of 

 cosmogonists, who see in every new Geological discovery 

 only an advanced post of science, which they, if auxiliaries, 

 would unwisely push beyond the point of security ; if 

 enemies, would as unwisely attack with their whole dis- 



