OF THE ORGANIC FOSSILS. 417 



surrender an hypothesis, and tenacious of it in propor- 

 tion to its weakness, Geologists have; invented the 

 term transition, partly to preserve this fanciful rule. 

 They are abundant in the latest argillaceous schists 

 and limestones of the primary series ; drawing that 

 line at the old red sandstone. 



In proceeding to consider the individual strata, I 

 may first remark that organic fossils have never oc- 

 curred in gneiss or in micaceous schist; as was to be 

 expected, a least in the predominant cases, from the 

 theory of those rocks formerly given. Yet, as the 

 latter rock is sometimes formed of fragments, it is 

 possible that they should be found in it. We have 

 no right to decide on the non-existence of animals 

 during this early stage of the earth, because we have 

 not found them. Though this rock has been exposed 

 to heat, the shells of shale are not always obliterated 

 under the same circumstances. If we make rules of 

 this kind,, we shall never search, and never know : 

 when we decide from negative evidence, we make our 

 ignorance the measure of what is. This negative 

 evidence as to an early creation is otherwise worthless ; 

 because, even in the secondary strata, organic bodies 

 are seldom found in siliceous rocks, and because there 

 is an evident comparative rarity of animal fossils in 

 retroceding, as would be proved by the scarcity of 

 primary limestone, were there no other evidence. 



This is the hypothetical suggestion of a doubt as to 

 one of the great rules of Geologists : it must now be 

 asked whether there be not evidence from which to 

 conjecture an organic creation of even this early date. 

 They have been unwilling to seek it, on account of 

 their hypothesis, or even to admit the possibility, when 

 produced. Anthracite is coal, and it is found in the 

 oldest rocks; while, under this hypothesis, it has been 

 VOL. r. E E 



