62 



THE GEOLOGIST. 



top to bottom, which clearly could not be done without that formation 

 being capped somewhere by a mass of the next overlying one, to show the 

 real top ; its bottom being shown by the outcrop of, or by wells being sunk 

 through to, the formation next below. 



6. Crag (of Prestwich). — Near the edge of the Chalk escarpment near 

 Folkestone, and to a smaller extent in other like places, there is found a 

 deposit of sand, often ferruginous, the age of which is not yet made out 

 with certainty. It seems not to be connected with any of the older 

 Tertiary beds, and it is not like any of the Drift-beds of the district. Prom 

 the occurrence of a peculiar set of fossils in a pipe of this sand in the Chalk 

 above Lenham, Mr. Prestwich was led to class it with the " Crag," an 

 Upper Tertiary formation of much later date than any we have been con- 

 sidering. The fossils, however, being only in the state of casts in iron- 

 stone, and merely from a small pipe, the evidence is hardly conclusive, and 

 the classification must be looked on as provisional. There is therefore a 

 very doubtful point in the Tertiary Geology of their county for the " East 

 Xent Naturalists " to work out. 



Geological Society. — December 2, 1863. — 1. "On the Correlation of 

 the Oligocene Deposits of Belgium, Northern G-ermany, and the South 

 of England." By Herr Adolf von Koenen. Communicated by F. E. 

 Edwards, Esq., F.G.S. Railway-cuttings in the New Forest (Brocken- 

 hurst, etc.) have recently exposed certain marine beds overlying the Lower 

 Headon (freshwater) series, and containing fossils hitherto unknown in 

 England, but which, as Herr von Koenen showed, constitute the marine 

 equivalent of the Middle Headon strata. 



The author gave an exposition of the current opinions upon the correla- 

 tion of those English and foreign " Upper Eocene " or " Lower Miocene " 

 strata, to which Professor Beyrich has given the name " Oligocene," and 

 briefly sketched their distribution and limits upon the Continent. He then 

 gave a list of fifty-nine New-Forest (Middle Headon) fossils, which he had 

 determined, and stated that, of this number, forty-six occur in the Lower 

 Oligocene of Germany, and twenty-three are characteristic of that forma- 

 tion ; twenty-one of these species occur in the Barton Clay, four in the 

 Middle Oligocene, and eight are peculiar to the Brockenhurst beds. He 

 therefore concluded that the Headon and Brockenhurst strata are on the 

 same horizon as the Lower Oligocene ; and he confirmed the opinion of pre- 

 vious observers, that the Hempstead beds are the equivalent of the " Gres 

 de Fontainebleau " and of the Middle Oligocene of Germany. 



2. " On the Liassic Strata of the Neighbourhood of Belfast." By Ralph 

 Tate, Esq., F.G.S. 



In the neighbourhood of Belfast the following members of the Lias for- 

 mation were stated to occur, namely : — The zone of Ammonites Bucklandi, 

 the White Lias, and the zone of Avicula contorta. 



The characters of these subdivisions in the district under consideration 

 were described in detail by Mr. Tate, who gave sections of the beds ex- 

 posed in Colin Glen and at Cave Hill, at which localities the three zones 

 are seen ; he also gave sections of the Avicula contorta beds as exposed at 

 Woodbarn and at Whitehead, and lists of the fossils found in the strata of 

 each subdivision at the localities mentioned, noticing that, in the zone of 

 Ammonites Bucklandi, that Ammonite is replaced by A. intermedins, the 

 other fossils being of the same species as occur in that zone in England ; 

 and he concluded with some general remarks on the distribution of the 

 members of the Lias in the North of Ireland. 



3. " Notes on the Devonian Rocks of the Bosphorus." By W. R. 



