Ob4 TKINCIPLES AND METHODS OF PALACONTOLOGY. 



have a series of local topographies, but no scieuce of geology; nor could 

 tljose great laws ever have been established by wliicli tlie geologist, 

 acquainted with the surface rock of a country, is enabled to predict with 

 much confidence what may, and what cannot, be found beneath it. 



These laws are in truth entirely based on the study of the "fossils" 

 contained in the rocks ; it is upon this science of fossils, or " palaeon- 

 tology,"* that another and most important method of determining the 

 nature and order of the strata rests. Universal experience has shown 

 that every series of strata contains assemblages of fossils which are 

 peculiar to and characteristic of it; which are usually found in it, and 

 never found out of it ; and observation has further demonstrated that 

 the strata thus characterized are arranged in an order of superposition 

 which is everywhere constant. It follows, therefore, that the fossils con- 

 tained in a stratum of rock are capable of revealing to us, at once, the 

 position of that stratum in the whole series, and of informing us what 

 lies above and what below it. 



A common example will illustrate the practical value of the informa- 

 tion thus obtained. 



It is shown by experience that in these islands extensive beds of good 

 workable coal are never found below that particular series of strata 

 termed, collectively, the " carboniferous formation." ^Nevertheless, fos- 

 silized vegetable matters occur in other strata, and have not unfre- 

 (luently misled owners of estates into undertaking ruinously exjiensive 

 and wholly fruitless mining operations, which Avould never have been 

 commenced had they availed themselves of the information aftbrded by 

 the fossils of the surface rocks. For it is clear that a preliminary exami- 

 nation of these fossils will show at once whether they belong to strata 

 below the carboniferous rocks or nbove them. If the former be the case, 

 then the sinking a shaft is absurd, as every blow of the pickaxe must 

 take the miner, in reality, further away from the object of his search; 

 if the latter, on the other hand, success is at any rate possible, though 

 the expediency of making the attempt will depend upon many contin- 

 gencies. 



i^Tow it is clear that, if the fossils contained in the rocks constituting 

 the surface in every district of Great Britain had been examined, it would 

 be possible, by coloring a map of these islands in such a manner that all 

 those parts whose fossils indicated their inferiority to the carboniferous 

 formation should be blue, and all those which lay above it should be red, 

 to indicate at once to the miner where his search for coal might possibly 

 be successful, and where it must necessarily fail. And, furthermore, if 

 the fossils on which the coloring was based were placed in a museum 

 for iiublic inspection, it would be open to every one to examine for him- 

 self the evidence on which the map stood, and to satisfy himself of the 

 accuracy of this part of the work of the surveyors. 



What is here supposed to be done with reference to this one set of 

 beds — the carboniferous formation — has, in effect, been performed by 

 the labors of the geological surveyors of Great Britain for all the strata 

 which enter into the comi)osition of the British Islands. The place 

 where each constitutes the surface rock is marked by an appropriate 

 color on the maps of the survey. The fossils which have served as the 

 standards of comparison in determining the nature of the strata are 

 open to general inspection in the Museum of Practical Geology. In one 

 sense, therefore, the collection of fossils is simply the product of and 

 key to the maps of the survey. 



* Palaeontology. — Derived from three Greek words, sigoifying ".lucieat" and 

 '■being " and " discourse." The science of ancient beines. 



