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828 STRATIGRAPHICAL GEOLOGY. [Boox VL 
lunata, O. vesicularis, Janira quadricostata, and numerous remains of Mosd- 
saurus and of chelonians, together with Voluta, Fasciolaria, and other 
characteristically Tertiary genera of molluscs.! Similar strata and 
fossils occur at Faxoe, Denmark. The terrestrial flora in the highest 
Cretaceous series at Aix-la-Chapelle has been already referred to (p. 803). 
Germany.—The Cretaceous deposits of Germany, Denmark, and the 
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south of Sweden were accumulated in the same northern province with — 
those of Britain, the north of France, and Belgium, for they present on 
the whole the same paleontological succession and even to a considerable 
extent the same lithological characters. It would appear that the western 
part of this region began tosubside before the eastern, and attained a greater 
amount of depression beneath the sea. In proof of this statement it may 
be mentioned that the Neocomian clays of the north of England extend 
as far as the Teutoburger Wald, but are absent from the base of the 
Cretaceous system in Saxony and Bohemia. In north-west Germany 
Neocomian strata under the name of Hils appear at many points between 
the Isle of Heligoland (where representatives of part of the Speeton 
clay and the Hunstanton red chalk occur), and the east of Brunswick, 
indicative of what was, doubtless, originally continuous deposit. In 
Hanover they consist of a lower series of conglomerates (Hils-conglome- 
rat), and an upper group of clays (Hils-thon). Appearing on the flanks 
of the hills which rise out of the great drift-covered plains, they attain 
their completest development in Brunswick, where they,attain a total 
thickness of 450 feet, and consist of a lower group of limestone and 
sandy marls, with Toxaster complanatus, Exogyra Couloni (sinuata), Ammo- 
nites bidichotomus, A. astierianus, and many other fossils; a middle group 
of dark blue clays with Belemnites brunswicensis, Ammonites nisus, Ancylo- 
ceras Emmerici, Exogyra Couloni (sinuata), &c., and an upper group of dark 
and whitish marly clays with Ammonites Martini, A. Deshayesi, A. nisus, ' 
Belemnites Ewaldi, Toxoceras royerianum, Crioceras, &c.2— Below the Hils- 
thon in Westphalia, the Harz, and Hanover, the lower parts of the true 
marine Neocomian series are replaced by a massive fluviatile formation 
corresponding to the English Wealden, and divisible into two groups: 
1st, Diester sandstone (600 feet), like the Hastings sand of England, 
consisting of fine light yellow or grey sandstone, dark shales, and seams 
of coal varying from mere partings up to workable seams of three and even 
more than six feet in thickness. These strata are full of remains of terres- 
trial vegetation (Hquisetum, Baiera, Oleandrideum, Laccopteris, Sagenopteris, 
Anomozamites, Pterophyllum, Podozamites, and a few coniters), also shells of 
fresh-water genera (Cyrena, Paludina), cyprids, and remains of Lepi- 
dotus and other fishes; 2nd, Weald clay (65 to 100 feet) with thin layers 
of sandy limestone (Cyrena, Cyclas, Unio, Melania, Cypris, &e.*), The 
Gault or Albian of north-western Germany consists, according to Von 
Strombeck, of two groups of strata. The lower of these, apparently 
unrepresented in England, consists of a lower clay with the zone of Ammo- 
nites milletianus, and an upper clay with Ammonites tardefurcatus. The 
' Dumont, Mém. Terrains Crétacés, &c., 1878. Mourlon, Géol. de la Belgique, 1880. 
* Von Strombeck, Zeitsch. Deutsch. Geol. Ges. i. p. 462; xiii, 20; N. Jahrb. 1855, 
pp. 159, 644; Judd, Q. J. Geol. Soc. xxvi. p. 343. 
* W. Dunker, Ueber den norddeutsch. Walderthon, u. 8. w., Cassel, 1844; Dunker 
and Von Meyer, Monographie der norddeutsch. Wdlderbildung, u. s. w., Brunswick, 1846 ; 
Heinrich Credner, Ueber die Gliderung der oberen Jura und der Wealdenbildung in 
nordwestlichen Deutschland, Prague, 1863, 

