

24 Prehistoric Races. 



may be relied on to interpret things rightly when 

 applied to the unknown. Here there is no suffi- 

 cient enumeration of facts to formulate any law. 

 Solitary facts known are compared with solitary 

 unknowns; and conclusions are jumped at from 

 such premises as logic will not admit, to begin 

 with. And the end of the argument corresponds 

 to the beginning. For when the hastily constructed 

 law, derived from a few known facts, is tested in 

 actual cases under our eyes, it is found so often 

 faulty in its sum total of years required to fossilize 

 a tree on the bank of the Mississippi, or to lay down 

 ten or twenty feet of loam, that, whenever geology 

 pretends to measure its time in terms of history, 

 we are perfectly justified in suspending our judg- 

 ment, until it has found a common denominator for 

 historical duration and its own duration — two very 

 different things. 



17. It does mark the order of succession, 



whether in the soils deposited, or in the objects 



which those deposits contain. It marks 



(•eology , r j 



inductive. too the relative proportion of duration, 

 which respective thicknesses of the stra- 

 tification seem to have required. But, with all that, 

 the conditions of earth, and water, and air, and sky 

 have been so different at the different periods of ter- 

 restrial evolution that, to read the lesson of strati- 

 fication aright, there would seem to be needed an 

 equipment of science on pretty nearly all the laws 

 of the universe. Astronomy, meteorology, geogra- 





