332 ILLOGICAL GEOLOGY. 



On this position, which seems a strong one, we have, in 

 the first place, to remark, that the evidence of correspond- 

 ence is always more or less suspicious. We have already 

 adverted to the several " idols " — if we may use Bacon's 

 metaphor — to which geologists unconsciously sacrifice, 

 when interpreting the structures of unexplored regions. 

 Carrying with them the classification of strata existing in 

 Europe, and assuming that groups of strata in other parts 

 of the world must answer to some of the groups of strata 

 known here, they are necessarily prone to assert parallel- 

 ism on insufiicient evidence. They scarcely entertain the 

 previous question, whether the formations they are examin- 

 ing have or have not any European equivalents; but the 

 question is — with which of the European series shall they 

 be classed? — with which do they most agree ? — from which 

 do they differ least ? And this being the mode of enquiry, 

 there is apt to result great laxity o€ interpretation. How 

 lax the interpretation really is, may be readily shown. 

 When strata are discontinuous, as between Europe and 

 America, no evidence can be derived from the order of 

 superposition, apart from mineral characters and organic 

 remains ; for, unless strata can be continuously traced, min- 

 eral characters and organic remains are the only means of 

 classing them as such or such. 



As to the test of mineral characters, we have seen that 

 it is almost worthless ; and no modern geologist would 

 dare to say it should be relied on. If the Old Red Sand- 

 stone series in mid-England, differs wholly in lithological 

 aspect from the equivalent series in South Devon, it is clear 

 that similarities of texture and composition can have no 

 weight in assimilating a system of strata in another quar- 

 ter of the globe to some European system. The test of 

 fossils, therefore, is the only one that remains ; and with 

 how little strictness this test is applied, one case will show. 

 Of forty-six species of British Devonian corals, only six 



