254 Prof, Sedgwick on the Origin [Apiul, 



a complete answer in the present state of our information. If, 

 Jiowever, a great many well observed facts seem to point to one 

 conclusion, that conclusion must be considered probable until it 

 is opposed by some other conflicting facts. One thing at least 

 is certain, that no hypothesis can be admitted which is not 

 borne out by that series of facts (however imperfect) with which 

 we are now acquainted. 



On these grounds I do not hesitate a moment in rejecting the 

 hypothesis which allows the formation of alluvial deposits in 

 the manner above described, but accounts for all the diluvial 

 phenomena by a succession of partial and transient inundations, 

 occasioned by the bursting of lakes, and other similar catastro- 

 phes.* In the first place, the cause assigned is inadequate to 

 the effects produced. The physical contour and structure of the 

 central and southern parts of England show the impossibility of 

 any large lakes ever having existed among our secondary strata, 

 capable of producing the enormous and almost continuous beds 

 of gravel which stretch along the eastern coast. Several striking 

 facts connected with this question have fallen under my own 

 observation ; and, as far as they go, confirm the general views 

 given in the " Reliquiae Diluvianse." As the description of 

 these facts will lead me into some details, I hope to resume the 

 subject in the next number of the Annals of Philosophy. 

 Secondly, the hypothesis is gratuitous. In many parts of 

 England, where there is abundance of superficial gravel, there 

 is not the shadow of evidence to prove that any great body of 

 water was ever pent up among the neighbouring strata, so as to 

 form a lake which afterwards burst the barriers by which it was 

 confined. Catastrophes of this kind sometimes happen in 

 mountainous regions, and the effects produced are commensu- 

 rate to the agents; but these effects have nothing to do with 

 the great masses of superficial gravel even in the contiguous 

 districts.f Thirdly, the feeble agents which the hypothesis 

 allows would require an indefinite extension of time before they 

 could produce such effects as the earth's surface plainly exhibits- 

 But the quantity of marsh land and silt formed at the head of 

 many lakes, the extent of different deltas, and other similar phe- 

 nomena, appear to demonstrate that all alluvial deposits have 

 been completed within a very limited period. :{: The hypothesis 

 is, therefore, inadmissible, which makes alluvial and diluvial 

 deposits contemporaneous, and implies an indefinite period of 



* This appears nearly to agree with Saussure's opinions', and is still held by some 

 geologists on the Continent. 



+ In consequence of the prevalence of local disturbing forces, such as those alluded 

 to in the text, the great relations of the superficial detritus cannot be studied to so much 

 advantage in the immediate neighbourhood of mountain chains, as in the lower regions 

 of the earth's surface. 



$ We owe this conclusion to Deluc who devoted the labours of many years to its con- 

 firmation. Had hi« labours terminated here, he had done great service to geology. 



