)]
[Illustration: Fig. 80.--_Cystiphyllum vesiculosum_, showing a
succession of cups produces by budding from the original coral.
Of the natural size. Devonian, America and Europe. (Original.)]
[Illustration: Fig. 81--_Zaphrentis cornicula_, of the natural
size. Devonian, America. (Original.)]
[Illustration: Fig. 82--_Heliophyllum exiguum_, viewed from in
front and behind. Of the natural size. Devonian, Canada. (Original.)]
[Illustration: Fig. 83.--Portion of a mass of _Crepidophyllum
Archiaci_, of the natural size. Hamilton Formation, Canada. (After
Billings.)]
No true _Graptolites_ have ever been detected in strata of Devonian
age; and the whole of this group has become extinguished--unless we
refer here the still surviving _Dictyonemoe_. The _Coelenterates_,
however, are represented by a vast number of _Corals_, of beautiful
forms and very varied types. The marbles of Devonshire, the Devonian
limestones of the Eifel and of France, and the calcareous strata
of the Corniferous and Hamilton groups of America, are often
replete with the skeletons of these organisms--so much so as to
sometimes entitle the rock to be considered as representing an
ancient coral-reef. In some instances the Corals have preserved
their primitive calcareous composition; and if they are embedded
in soft shales, they may weather out of the rock in almost all
their original perfection.
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