On the banks of the Maes, however, near
Maestricht in Holland, there occurs a series of yellowish limestones,
of about 100 feet in thickness, and undoubtedly superior to the White
Chalk. These _Maestricht beds_ (_Danien_ of D'Orbigny) contain a
remarkable series of fossils, the characters of which are partly
Cretaceous and partly Tertiary. Thus, with the characteristic
Chalk fossils, _Belemnites, Baculites_, Sea-Urchins, &c., are
numerous Univalve Molluscs, such as Cowries and Volutes, which
are otherwise exclusively Tertiary or Recent.
Holding a similar position to the Maestricht beds, and showing
a similar intermixture of Cretaceous forms with later types, are
certain beds which occur in the island of Seeland, in Denmark,
and which are known as the _Faxoee Limestone_.
Of a somewhat later date than the Maestricht beds is the _Pisolitic
Limestone_ of France, which rests unconformably on the White
Chalk, and contains a large number of Tertiary fossils along with
some characteristic Cretaceous types.
The subjoined sketch-section exhibits the general succession of
the Cretaceous deposits in Britain:--
[Illustration: Fig. 185. GENERALIZED SECTION OF THE CRETACEOUS
SERIES OF BRITAIN.]
In North America, strata of Lower Cretaceous age are well represented
in Missouri, Wyoming, Utah, and in some other areas; but the greater
portion of the American deposits of this period are referable to
the Upper Cretaceous.
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