;36C MacCulloch's System of Geology. 



quires lies between the date of deposition of these two rocks. 

 Ignorant of the niceties of discrimination of fossil species, or 

 possibly, of mineral character, he refers to the descriptive geo- 

 logist to assign the respective places of the two rocks in the 

 system, who may perhaps know nothing of the purposes which 

 this determination is to serve. Is fhe doctrine of parallelism 

 of chains of synchronous elevation more or less satisfactorily 

 determined by the co-operation of these two observers than if 

 one only had been employed ? It were easy to multiply illus- 

 trations. 



Considering the vast multiplicity of sciences, many of them 

 burdened with enormous technical labour, which become ne- 

 cessary to a complete geologist, it were vain to look for such 

 a " perfect monster. 1 ' Mechanics, dynamics, hydrostatics, 

 pneumatics, chemistry, mineralogy, botany, zoology, are but a 

 portion of the encyclopedaical knowledge with which he ought 

 to be familiar, several of which individually become the labour 

 of a lifetime fully to master : Hence a certain subdivision of 

 labour has been successfully resorted to, and even the natural 

 historical school of geologists often depend for their technical 

 facts upon the authority of a single individual who has studied 

 the subject. The moment a doubtful fossil is presented to the 

 o-eological society, if it be a bone, it is put into the hands of 

 Mr Clift; if a shell, Mr Sowerby gives his verdict; if an insect, 

 Mr Kirby ; if a plant, Mr Brown or Mr Lindley. This is 

 as it should be ; but in the higher divisions of the science a 

 similar plan should be followed ; the physics of geology should 

 not be made subordinate to, but distinct from pure natural 

 history. The ponderous and most elaborate volumes of the 

 Geological Transactions contain piles of facts, but the spirit in 

 which they are treated seems to indicate a trivial standard as 

 the ultimate aim of the geologist. To determine to which 

 subordinate stratum of a large group a particular rock is to be 

 referred, is often considered a most important question as a 

 matter of fact, yet it rarely happens that such a determination 

 is capable of leading to the revelation of a class of general 

 laws. Though we had a perfect geological map of the globe, 

 the minds which were engaged in its construction might be 

 quite incapable of drawing any valuable conclusion from it, 

 and in precisely the same way we might consider the author 



