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species, which he calls Nematophycus Hicksii. The resemblance generally 
between this very early (probably oldest known) flora, and the far more 
recent Devonian, is very marked, and indicates a tolerable uniformity in the 
character of the conditions, at those widely separated periods. The strati- 
graphical position of these plant-bearing beds may be stated to be about 
the horizon of the Llandovery rocks. They are shown in the Survey sections 
to rest immediately upon the Bala series, and some of the beds are even 
included in that group. The animal remains found in the same beds are 
all of marine forms, and the species would seem to indicate a gradual 
passage from Lower to Upper Silurian. The evidence seems to show that 
at this mid-Silurian period the immediate area where the plants are now 
discovered must have been under water, and that the mixture of marine and 
dry-land plants took place in consequence of floods or rapid marine denu- 
dation. The author indicated that the land-areas must have been to the 
south and west, chiefly islands, surrounded by a moderately deep sea, in 
which Graptolites occurred in abundance. ( Geol . Soc. Proci) 
The Jurassic Rocks of England and France. — On the 27th April last the 
Rev. J. F. Blake communicated a most important paper to the Geological 
Society, in which he attempted to settle the many questions of correlation 
arising out of the detailed descriptions given of the various localities in the 
Paris basin where Upper Jurassic rocks are developed, by a consecutive 
survey of them all, undertaken by the aid of a grant from the 1 Government 
Fund for Scientific Research.’ In previous papers the names used for the great 
subdivisions and their boundaries were adopted without material modifica- 
tions ; in the present such modifications were proposed as may bring the 
English and Continental arrangements into harmony. 
Five distinct areas were considered in this paper : 1 . The Southern 
range ; 2. The Charentes ; 3. Normandy ; 4. The Pays de Bray ; 5. The 
Boulonnais. 
1. The Southern Range. — This is continuous from the Ardennes through 
the Meuse, Yonne, &c., to the Cher. In the Ardennes the 1 Ferruginous 
Oolite ’ corresponds to our Osmington Oolite, and to the Lower Limestones 
and Passage-beds of Yorkshire, the underlying ‘ Middle Oxfordian’ being 
equivalent to our Lower Calcareous Grit. Above comes immediately the Coral 
Rag with Cidaris florigemma ; and the stratigraphical and palaeontological 
break is constantly between the Coral Rag and Ferruginous Oolite when that 
occurs. The Corallian is a well-marked formation, though its character is 
variability. It is divisible generally into two groups — Coral Rag and Supra- 
coralline beds, the latter usually being the ‘Diceras- beds ;’ but in the Yonne 
there is a great development of ‘ Diceras- beds below, associated with Cidaris 
florigemma, and massive corals, which are gradually introduced in going west. 
This part of the series in the Haute Marne has been described as very dif- 
ferent; but the author did not at all agree with M. Tombeck’s strati- 
graphical determination, and considers the ‘ Oolite de la Nothe ’ no more 
than the continuation of the Supracoralline Diceras- beds, which he considers 
to uniformly overlie and never to underlie the Am. marantanus marls, which 
latter are Oxfordian. In fact nothing abnormal occurs in this Department. The 
whole series has a tendency to degenerate into barren lithographic limestones, 
in which distinctions are lost. The Astartian and Virgulian beds were 
