Professor Forbes on iJie Geology of Auvergne. 3 



facility with which the analogies of their science were received 

 as the canons of geology.* The consequence has been, that 

 geology, of late years, has become little more than a commenta- 

 ry on organized fossils. The great ends of the science seem to 

 have been forgotten, and strata are no longer examined in the 

 hope of detecting the proof of any mechanical or chemical change, 

 but simply for the sake of classifying a new plant, shell, or rep- 

 tile. The Dynamics of Geology have been overlooked, or, if 

 adverted to, have been engaged in (too often) with partial views 

 and inadequate preparation. 



Yet it is to this point that the exertions of the geologist might 

 be successfully apphed. His object is the inquiry into the na- 

 ture of changes which have supervened in the condition of the 

 earth's surface. Such changes are of two kinds, mechanical and 

 chemical ; to investigate these, we might naturally expect that 

 natural philosophy and chemistry would be thought essential, — 

 but geologists in general have brought to their task but a very 

 slight acquaintance with those sciences. I am persuaded that it 

 will be by drawing the attention of three classes of persons, viz. 

 natural historians, chemists, and natural philosophers, to this 

 one very complicated but very important subject, that any real 

 advances are to be made, and perhaps even the alphabet of the 

 science of geology is scarcely yet formed. The natural hi^brian 

 is to collect the facts or data of the problems upon which the 

 others are to reason ; and such a division of labour has, we all 

 know, been productive of the highest benefit to every one of the 

 mixed sciences. Such geology undoubtedly is, and one, we are 

 persuaded, even more complex than is commonly imagined. The 

 ordinary theories of geological change often refer to purely hy- 

 pothetical cases, much simpler than those which occur in nature* 

 The mode of action of the forces unanimously admitted into 

 geology is in reality so complex, that to expect to trace an imme- 

 diate analogy between the conclusions of mere reasoning and 



• " II nest bruit tjue des hautes revelations faites par la zoologie au profit 

 de la g^ologie, et que cette derni^re avec toute confiance et docility se trouve 

 avoir acceptees est adapt^es aiix principales base? de sa theorie. Pour moi, 

 je ne partage pas Tidee qui a seduit taut de personnes, et je pense tout au 

 contraire que I'importation n'a pas et6 aussi heureuse et aussi utile qu'on ue 

 la croit generalement."— Geo/ro^ St Hilaire, qu^ed *y BouL 



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