1865.] Jenkins on Strata identified by Organic Remains. 623 



recent did the fossil faunas become. This induction was quickly fol- 

 lowed by an attempt at classifying the rocks into great systems and 

 subordinate formations and beds ; but into the details of these efforts 

 I need not enter. Naturally the next step was to compare the forma- 

 tions of different countries, to ascertain the coincidences, and to find 

 out the gaps. And thus we come to the line of research that first 

 suggested a modification of the accepted doctrine, — " Strata Identified 

 by Organic Remains." 



Englishmen have generally been foremost in every field, from 

 breaking stones as geologists to scaling the Matterhorn ; and, as Sir 

 Roderick Murchison has just remarked, in his Presidential Address to 

 the Geological Section of the British Association, the great divisions 

 of Silurian, Devonian, and Carboniferous, first established in England, 

 have been adopted on the Continent. The attempt to correlate the 

 formations of different countries was pursued with great zeal and good 

 results, and at first without endangering the universal application of 

 William Smith's great law ; but as Palaeontology advanced, her 

 votaries became more critical, and infinitely better naturalists, and 

 they found that, as the distance between similar formations increased, 

 the proportion of identical species became smaller. The explanation 

 generally given and readily received was, that this difference in 

 organic contents was due to difference of latitude and to local modify- 

 ing causes, and thus " Strata Identified by Organic Remains " continued 

 to be accepted both as a motto and a law, a foundation of faith on 

 which the whole structure of modern Geology was built, and the truth 

 of which was unassailable. 



Such being the state of Geological opinion, what was the astonish- 

 ment of the Fellows of the Geological Society when, at one of their 

 meetings in March, 1846, Professor Edward Forbes declared " that 

 identity of fossils in strata geographically far apart must lead to the 

 inference that the beds were of different, not, as hitherto maintained, 

 of the same age."* But although Geologists were astonished, and 

 perhaps, as Edward Forbes expressed it, " terrified," their astonish- 

 ment or terror took no practical shape. The promulgator of this new 

 doctrine, like most men of genius, was in the habit of giving vent to 

 apparently strange ideas, some of which were the result of careful 

 observation, combined with great extraneous knowledge and a powerful 

 imagination, while others were due to the imagination alone, and 

 required time for their merit to be acknowledged. Accordingly his 

 heresy did not produce any permanent effect at the time, notwith- 

 standing the " terror " it excited, and it was not until sixteen years 

 afterwards that the subject was revived in a manner sufficiently 

 authoritative to challenge public attention. Then, in 1862, Professor 

 Huxley took the opportunity afforded by an Anniversary Address to 

 the Geological Society to bring this heterodox doctrine again before 

 the notice of that learned body, and since then several of the younger 

 palaeontologists have given the idea its due weight in endeavouring to 

 correlate distant deposits. 



* Vide Wilson and Geikie's ' Memoir of Edward Forbes,' p. 395 



