ANNIVERSARY ADDRESS OF THE PRESIDENT. Ixxix 



epoch, between the close of the Lower and the commencement of the 

 Upper Silurian periods, at which there is distinct evidence in Wales 

 of a movement having taken place, though not one generally of great 

 magnitude. According to any theory of elevation it might probably 

 appear remarkable that no movement of a distinctive character shoixld 

 have taken place at either of the above epochs, at which such remark- 

 able transitions took place in the types of organic life over a large 

 portion of the globe, but it would seem especially remarkable when 

 viewed with reference to a theory admitting so few epochs of dis- 

 turbance. 



This system is probably the best defined of any of those European 

 systems recognized by M. de Beaumont. It undoubtedly exists 

 over a large portion of the Palaeozoic rocks of these islands, admitting 

 local deviations in the directions of strike to a considerable amount, as 

 must be done, if we include in the system both the S.E. of Ireland and 

 the Grampians. It is important here, however, to recollect, that this 

 movement can have produced scarcely an appreciable effect, as I have 

 already shown (p. Ixxiv), in the region of S. Wales and the adjoining 

 counties of England. We may also observe that its epoch is widely 

 separated from that of any anterior or posterior recognizable great 

 movement. 



The system of the Gallons (mountains in Alsace) is our author's next 

 system in order of time. He supposes it to have been produced between 

 the periods of the Carboniferous Limestone and Millstone Grit. The 

 age of this system, and consequently the contemporaneity of the lines 

 composing it, appear to me very unsatisfactory. I cannot recognize 

 in this country any movements of this epoch, because I believe that 

 no example has ever yet been observed of a sensible unconformity 

 between the Mountain Limestone and Millstone Grit in these islands, 

 at any point where the junction of the two formations is visible. 

 There may be overlaps of the superior formation, but not such as to 

 indicate an appreciable difference in the dips of the beds of the two 

 formations in the same locality. I cannot, therefore, agree to refer, 

 for example, the great disturbance in the valley of the Dee in N. 

 Wales, on the north of the Berwyns, to a movement at the epoch in 

 question, while I believe the Millstone Grit and Carboniferous Lime- 

 stone to be in perfect conformity within a few miles of this locality, 

 and in every other part of these islands. The author refers to phse- 

 nomena in the immediate neighbourhood here spoken of, for the 

 establishment of the epoch of this movement ; but on consulting the 

 Ordnance Geological Map, instead of the imperfect maps which he 

 appears to have consulted, it is easily seen that no discontinuity 

 between the two formations in question is indicated. But the epoch 

 of this system is avowedly doubtful. 



The system of Forez dates, according to our author, between the 

 Millstone Grit and the Coal-measures. It is founded on observations 

 of dislocations in the mountains of Forez in the department of the 

 Loire. In this country the system is supposed to embrace the anti- 

 clinal which runs N.N.W. in the southern part of the Dudley coal- 

 field, as already described (p.lxxvi), Cross Fell, Derbyshire, and one or 



