622 Original Articles. [Oct. 



STRATA IDENTIFIED BY ORGANIC REMAINS. 



By H. M. Jenkins, F.G.S , Assistant-Secretary of the Geological 



Society. 



' Strata Identified by Organized Fossils ' was the title of a well- 

 known work by William Smith,* in which he illustrated his discovery 

 that the numerous formations constituting the crust of the earth could 

 be distinguished and identified by means of their imbedded fossils. 

 The term " organized fossils " was used by this celebrated author 

 because all kinds of imbedded minerals and stones, whether of organic 

 origin or not, had previously been called " fossils ; " but, as the latter 

 epithet became restricted in its meaning, so as to be synonymous with 

 the former, the term " organized fossils " became obsolete, and " fossils " 

 were spoken of simply as such, or as " organic remains ; " thus we 

 arrive at the origin of the title of this article, — " Strata Identified by 

 Organic Remains." In these pages I shall endeavour to examine the 

 present state of geological opinion respecting this great generalization 

 of the " Father of English Geology," as William Smith has been 

 appropriately styled, for his discoveries, especially the one which now 

 most concerns us, have undoubtedly been the foundation of all modern 

 Geology. 



This discovery gave a new direction to geological inquiry. Before 

 its promulgation geologists had been contented to describe strata as so 

 many rocks and minerals, having certain peculiarities of dip, strike, 

 colour, hardness, and so on ; and the imbedded fossils were merely 

 considered to be extremely curious and more or less adventitious ; in 

 fact, they were at one time called " extraneous fossils," a term which 

 has since obtained a widely different and very much restricted mean- 

 ing. Afterwards, however, they necessarily became invested with a 

 higher interest, for they were shown to be not only curious, but also 

 extremely useful and important. Zoology and Botany received a great 

 impetus, both on account of the light they threw on the nature of 

 fossils, and because of the number of new and curious organisms 

 discovered in the fossil state, which helped to explain aberrant 

 recent forms. It was now, also, no longer necessary to trace a con- 

 tinuation between the rocks of two or more localities to be assured of 

 their identity ; if they contained the same fossils, they were as abso- 

 lutely " identified " as if their physical continuation were exposed 

 along their whole line of strike. Henceforth the labour of tracing the 

 distribution of strata was very much reduced, as also were the chances 

 of error ; consequently the characters of fossils received a vast amount 

 of attention, and their study rapidly became a science of itself, and 

 this new science — Palaeontology — has completely changed the aspect 

 of its parent, and in many instances has altered its language. 



Palaeontologists were soon enabled to show that the older the 

 stratum whence organic remains were derived, the less resemblance 

 did the fossils bear to recent organisms, and the more dissimilar to the 



* Published in 1817. 



