NATURAL HISTORY OF CREATION. 49 



when we hear of carbon beginning to appear in the 

 ascending series of rocks, we are nnavoidably led to 

 consider it as marking a time of some importance in the 

 earth's history, a new era of natural conditions, one in 

 which organic life has probably played a part. 



It is not easy to suppose that, at this period, carbon 

 was adopted directly in its gaseous form into rocks ; for, 

 if so, why should it not have been taken into earlier ones 

 also ? But we know that plants take it in and transform 

 it into substance, and we also know that there are classes 

 of animals (marine poh^pes) which are capable of appro- 

 priating it, in connexion wdth lime (carbonate of lime), 

 from the waters of the ocean, provided it be there in 

 solution ; and this substance do these animals deposit in 

 masses (coral reefs) equal in extent to many strata. It 

 is also fully ascertained of many strata of limestone 

 higher in the series, that they are simply reefs of that 

 kind changed by subjection to heat and pressure. 



The appearance, then, of limestone beds in the early 

 part of the stratified series, strongly suggests the fact of 

 the commencement of organic life upon our planet, though 

 we cannot say that any of its special forms are made clear 

 to our eyes. 



It may not be out of place here to remark, that carbon 

 is presumed to exist largely in the interior of the earth, 

 from the fact of such considerable quantities of it issuing 

 at this day, in the form of carbonic acid gas, from fissures 

 and springs. The primeval and subsequent history of 

 this element is worthy of much attention, and we rhall 

 have to revert to it as a matter greatly concerning our 

 subject. Sir Henry De la Beche estimates the quantity 

 of carbonic acid gas locked up in every cubic yard of 

 limestone at 16,000 cubic feet. The quantity locked up 

 in coal, in which its basis, carbon, forms from 64 to 



