1869. ] DUNCAN—CORAL FAUNAS OF WESTERN EUROPE. 61 
of Madreporaria, including compound forms of reef species. A large 
coral bank, from 8 to 10 metres in thickness, runs obliquely through 
a vast depth of marine deposits, and it may be traced as far as the 
south side of the Lake of Geneva. The position of this bank, which 
is nearly composed of one species of coral, is such that it must have 
grown during a slow subsidence of the area. All these deposits con- 
tain fossils which are closely allied to the St-.Cassian forms; and 
some are identical species. 
Linas. 
1. Zone of Ammonites planorbis and its equivalents.—The corals 
of this zone in England belonged to reef-species ; and it is therefore 
probable that some scattered reefs were formed on our area during 
the considerable alterations in depth which the Ostrea and Ammonites 
zones indicate. Probably the reefs of the Alpine area still con- 
tinued. 
2. Zone of Ammonites angulatus.—The formation of fringing reefs 
and coral banks took place in the Glamorganshire area *; and the 
mountain-limestone supported them. Other reefs were formed in the 
north about Skye, and eastwards in Worcestershire. In Lincolnshire 
there were deep-sea conditions, and they prevailed also in the north 
of Ireland. Sparsely distributed reefs and deep seas may be traced 
in Northern and Eastern France and into Germany. ‘The reefs on 
the Lombardo-Alpine area persisted. It must be remembered that 
Triassic fish lived through the Rheetic period into the times when the 
deposits now being considered were forming, and that species of 
Triassic corals and mollusca formed part of their fauna. There 
were 617 species of corals on the British area. It would appear that 
the seas were full of a very rich invertebrate fauna during this 
period, and that the British, French, Belgian, and northern Italian 
districts were reef-areas. 
3. Zone of Ammonites Bucklandi (bisulcatus).—The reefs appear 
to have diminished, and to have been worn down, before the peculiar 
deposits contaiming this Ammonite were formed. In England, the 
remains of the scanty coral fauna of the reefs of this period are seen 
to cover up those of the reefs of the zone of Ammonites angulatus in 
Glamorganshire. The sea of the age of Ammonites Bucklandi con- 
tained a few of the molluscan species of the previous reefs ; but the 
bulk of their coral fauna is not to be recognized in its deposits, even 
by allied species. The area of England was losing the external 
conditions which hitherto and since the Trias had been gradually 
becoming more and more favourable for reef-formation. The coral- 
liferous deposits of Western Europe are as scanty in Madreporarian 
remains as those of England; and it therefore would appear that 
the reefs initiated during the Muschelkalk age had, after a long con- 
tinuance, gradually broken up, the variation in their consecutive 
faunas having been slight. 
The other divisions of the Lower Lias and those of the Middle 
* Quart. Journ. Geol. Soc., Feb. 1867. 
+ Dunean, Pal. Soc. Monog. Liassic Corals, vol. xx. 
