ANNIVERSARY ADDRESS OF THE PRESIDENT. xlix 



palseontological relations of the British strata, from the Laurentian 

 to the Permian rocks, we find, that 



From the Laurentian to the top of the Silu- 

 rian rocks there are 6 physical breaks. 



In the Old Eed Sandstone 2 „ ,, 



In the Carboniferous strata, probably at least 1 „ ,, 



Between the Carboniferous and Permian .... 1 ,, ,, 



10 in all. 



Except in one case where the rocks are almost barren, these 

 breaks are accompanied by great and remarkable changes in the 

 number and nature of the fossils, sometimes of the genera, and 

 always of the species. The coincidence is certain ; and the question 

 must present itself to every informed mind, Why does this arise ? 



Within the memory of most of us the ready answer would gene- 

 rally have been given, that each formation, the fossils of which are 

 distinct from those below and above, was complete in itself, and 

 presented a perfect view of the relics of the marine life of the world 

 for a given period ; that this life, by a distinct act of omnipotence, 

 was suddenly extinguished, and as suddenly replaced by a universal 

 new creation when the succeeding deposits began. 



The doctrine of per-centages common to two or more formations, 

 especially in the Tertiary strata, has so completely destroyed this 

 old notion, that I need not argue it here. 



The idea of the sudden destruction of entire faunas has again often 

 been expressed in another form : — viz., that certain given periods 

 were brought to an end by tremendous and universal convulsions, 

 which were the direct means of the destruction of all or nearly all 

 the life of the globe. Then, this temporary chaos having come to 

 an end, a new creation and new unconformable formations were 

 commenced with the return of order. Such opinions, common not 

 long ago and not yet quite extinct, are founded, often unconsciously, 

 on the assumption that the succession of known formations, and 

 therefore of life, is altogether or nearly complete. That it did not 

 require chaotic convulsions to destroy the old life and usher in the 

 new, is plain from the circumstance that the Oolitic epoch in a vast 

 area came to an end without any violent disturbance of the strata ; 

 for the Oolitic formations seem to have been quietly, and nearly 

 horizontally raised above the water (whence the origin of the 

 Purbeck and Wealden beds), and as quietly let down again. But 

 the diversity of the Oolitic and Cretaceous fossils is as complete 

 as if accompanied by violent disturbance and unconformity. The 

 accompaniment of this diversity is time, so strongly expressed in the 

 old delta, which tells of the drainage of a vast continent, followed 

 by the swallowing up of that land by the sea. The study of the 

 Tertiary strata has, however, been the chief means of destroying the 

 belief in the disappearance of faunas being necessarily accompanied 

 by sudden convulsions ; and therefore the worn-out theory sinks 



vol. xix. e 



