﻿MURCHISON FLINT DRIFT OF S.E. ENGLAND. 



391 



certain bands of the earth was equally due to the violent and sudden 

 fractures, heaves, and immersions (not mere upheavals) to which such 

 tracts were subjected. I believe this, not only from the proof so 

 clearly afforded of parent rocks having been then split up and of their 

 having thrown off quantities of angular debris, but also from the oc- 

 currence of the heaps of fractured bones of our aboriginal Oxen and 

 other Herbivores which are piled up in confused masses in the mud, 

 clay, sand, and pebbles in the deep clefts and fissures of many of our 

 clean-denuded rocks. The hills, in short, have been swept, and the 

 hollows have been filled. 



On the other hand, just as the water-worn and raised beaches of 

 the coast indicate a previous tranquillity and long-continued ordinary 

 action, so the caves which were first inhabited during former ages by 

 Hyaenas and other quadrupeds, prove to us the lengthened period of 

 quiescence that prevailed upon the land anterior to the grand con- 

 vulsions under consideration, and by which, as I think, the cold or icy 

 period was ushered in. 



On fair evidences we may also infer, that a long epoch followed the 

 physical changes in question, in which glacial conditions both sub- 

 aerial and subaqueous prevailed in the Northern hemisphere. But 

 even during the great oscillations which preceded and accompanied 

 such glacial epoch, including the re-elevation of vast sea-bottoms into 

 continents, there are proofs that many of the former great animals 

 escaped destruction ; doubtless by taking refuge on lands unaffected, 

 one of these having been preserved alive to our present time in the 

 Bos Aurochs of Lithuania * . This fact will account for another epoch 

 of cavern-animals subsequent to the glacial epoch, as indicated by 

 Professor E. Forbes f. 



Nothing indeed is further from my wish (and all my writings tes- 

 tify it) than to inculcate the belief that the former changes of the 

 surface, however they were in my opinion more paroxysmal and grand 

 than any of our era, were ever so general as to destroy whole races 

 of animals. I have invariably contended that ail physical disrup- 

 tions of the crust are local. In this sense each drift is local and 

 must have reference to its own cause. On the other hand let me 

 say, that the endeavour to refer all former fractures of the strata 

 as well as their overthrow on a great scale, as in the Alps, to causes 

 of no greater intensity of action than those which now prevail, is in 

 opposition to the observations I have made in every mountain-chain, 

 as well as in the modest cliffs of Brighton and Dover. 



Surely practical geologists can easily draw a distinction between 

 the quakes which the earth now undergoes or has undergone in the 

 historic era, and the profound rents and enormous changes of level to 

 which it was subjected in former periods. 



My conviction is, that, by including all ancient geological phseno- 

 mena in the category of existing intensity of causation, the able men 

 who have espoused that view have, in their too great eagerness to ex- 

 plain much that is still obscure, forced the former energy of nature 



* See Russia in Europe, vol. i. pp. 503, 638. 



f Memoirs of the Geological Survey of Great Britain, vol. i. p. 394. 



