Rev. Dr. Irving — Elevation of the Weald. 407 



Anglo-Gallic sea and deposition of the Oligocene strata, with which 

 the Tertiary record closes in the Paris and Hampshire Basins ; 

 (iii) the absence of marine deposits of Miocene age; (iv) the great 

 palseontological break between the Oligocene and the Crag, " not 

 a single species in any class being common to these two series in 

 Britain." 1 Further reflection during recent years upon the signifi- 

 cant fact, that we have no trace of Miocene marine deposits in the 

 South-East of England, has led me to the conclusion that the 

 Wealden and Tamisian areas were " dry land," and therefore under- 

 going subaerial waste and degradation all through that period of 

 geologic time and on into the Pliocene, as, in fact, Prof. Zittel has 

 represented matters in his Map of Middle Europe in Miocene times. 2 

 Mr. Etheridge appears to have arrived at the same conclusion, as 

 he has remarked (op. cit. p. 651), "Britain, so far as we know, was 

 a land-surface forming part of the continent during part of the 

 Miocene period." We may therefore hesitate to follow Professor 

 Prestwich in dating the great elevation of the Weald posterior to 

 the Miocene. 3 The commencement of this elevation is referred by 

 Zittel (op. cit. p. 433) to the Oligocene period, a simultaneous 

 depression of North Germany occurring, so that the waters of the 

 North Sea overflowed that region as far south as Bonn, and washed 

 the flanks of the Hartz and Thuriugian mountains. Credner 4 gives 

 a more detailed description of this, and tells us that this depression 

 continued on a more restricted scale during the Miocene, the 

 Tertiary deposits of North Germany being exclusively of Oligocene 

 and Miocene age, the Oligocene strata of that region being partly 

 marine, partly terrestrial, the latter yielding the chief supply of 

 brown-coal. At various points in North-western Germany — 

 Schleswig, Hoistein, Lauenburg, West Mecklenburg, Northern 

 Hanover — Miocene strata are recognized ; and they appear to stretch 

 away to the south-west through Oldenburg and Westphalia to 

 Hasselt and Antwerp, being recognized by Von Koenen as con- 

 temporaneous deposits, differing only in their physical facies from 

 those of his Diestian and Bolderian system. 5 This Miocene and 

 early Pliocene basin may repi'esent the area of depression on the north 

 side of the region of Miocene elevation (which included the present 

 regions of the Weald, the English Channel in its eastern portion, 

 and the north of France), and seems to have corresponded with a 

 similar depression of the Loire basin, where the Tertiary record 

 commences with the Miocene. These alterations of level were some 

 of the minor incidents of those great changes of contour of Central 

 and Western Europe, which are recorded in the Alps and Carpathians, 

 and perhaps most markedly in the Pyrenees (where the Nummulitic 

 Limestone is lifted up to the crests of mountains more than 10,000 



1 Etheridge, "Manual of Geology," p. 652. 



2 " A us der Urzeit" (Uldenbourg, Munich), p. 459. 



3 See also Ramsay, "Phys. Geol. and Geog. of Great Britain" (5th ed.), 

 pp. 274, 356. 4 " Elemente der Geologie " (6th ed.), pp. 695-703. 



5 Credner, op. cit. p. 714. If we follow Mr. O. Keid in relegating the Diestian 

 to the older Pliocene, these North German deposits may be of Pliocene age also ; but 

 this is a detail which does not much affect the general argument. 



