Ixxxiv PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



and in Germany, and M. de Beaumont supposes that the Oolitic 

 escarpment of this country may be due to it. This last conclusion 

 is manifestly very vague. 



The thirteenth system of our author is that of Mont Viso and 

 Pindus. The former is a mountain in the French Alps. The epoch 

 of the system is placed immediately after the Lower Cretaceous 

 formation, including the Firestone of the Upper Green Sand in 

 Kent, and the Craie chloritee and Craie tufeau of the French. It 

 appears to have been chiefly recognized in Central France and 

 Greece. 



The system of the Pyrenees presents itself next in the order of 

 time. Its direction is W.N.W. and E.S.E. Its epoch is imme- 

 diately after the Nummulite formation. It appears to have no re- 

 presentative in the interior of France or in the Peninsula, but is 

 widely developed more easterly in southern Europe. The elevation 

 of the Weald and the Bas Boulonnais is also partly assigned to this 

 system. 



I have given a very detailed description of the geological structure 

 of the Weald and Bas Boulonnais in a paper which is the last pub- 

 lished in the ' Transactions ' of this Society. The lines of elevation in 

 this district bemg curved lines, present the difficulty of which I have 

 already spoken in ]M. de Beaumont's theory. He endeavours to 

 meet it by assigning the elevation of the Weald to three distinct 

 epochs, so that it forms, according to this view, a part of three dif- 

 ferent systems — those of the Cote d'Or, the Pyrenees, and the Isle 

 of WigJit. My great objection to this view is, that it rests on the 

 gratuitous assumption, for Avhich not the slightest independent evi- 

 dence is offered, that different portions of this district were elevated 

 at different epochs, at which their respective lines of elevation were 

 produced. The dislocations of the Bas Boulonnais are referred to an 

 ante-cretaceous period ; those of the south-eastern part of the Wealden 

 to that immediately preceding the Plastic Clay; and thelinesof the more 

 eastern portion, extending into Wiltshire, to the period of the middle 

 Tertiaries. Of the two first assumptions there is no proof whatever, 

 except that deduced from the theory of parallelism itself. At the 

 same time there exists throughout this district as complete a cha- 

 racter of continuity as in any district with which I am acquainted; and 

 if we are ever to reason on the principle that unity of character in 

 observed pliBenomena must be regarded as indicative of a corre- 

 sponding unity in the cause to which those phsenomena are to be 

 attributed, this is not, in my opinion, a case in which we are at liberty 

 to deviate from that obvious rule for the guidance of our philoso- 

 phical speculations. The district is a limited one, and its lines of 

 elevation are consequently placed in close juxtaposition ; their pa- 

 rallelism, so far as the term can be applied to curved lines, is pro- 

 bably more nearly exact than in any one of the systems to which 

 our author would refer them ; and there is no evidence, as I have 

 already remarked, to authorize our referring them to three distinct 

 epochs. And yet, according to M. de Beaumont's theory, phseno- 

 mena thus closely allied are to be allowed no claim to a common 



