12 BRITISH FOSSIL CORALS. 
CHAPTER IT. 
CORALS OF THE LONDON CLAY. 
Tne Eocene deposits, known by the name of London Clay, contain various Corals, 
most of which belong to the two subordinate forms predominant among the Polypi of the 
present period, Zoantharia aporosa and Zoantharia perforata; but none of these organic 
remains can be considered as appertaining to species now im existence, or even to those 
found in the more recent tertiary formations. The general aspect of this portion of the 
fossil Fauna of England resembles very much that of the Corals imbedded in the 
“Calcaire grossier”’ of the Parisian basin. Some species, such as Zurbinolia sulcata, 
Stylocenia emarciata, Stylocenia monticularia, and Holarea Parisiensis, are common to 
both these localities ; but most of those found in the Eocene strata of the environs of Paris 
have not been met with in the London Clay, and many of the Corals belonging to these 
last-mentioned deposits have not been discovered elsewhere. Thus the London Clay 
appears not to contain any Milleporidee, Madreporide, or Lophoserinz, families which have 
various representatives in the Fauna of the Calcaire grossier, and the only Parisian fossil 
Coral referable to the order of Alcyonaria is a Distichopora;. whereas both Pennatulide 
and Gorgonidee have been met with in the London Clay. At the present period similar 
differences exist at small distances in the same zoological region, and appear to depend 
principally on the depth of the sea and the nature of the bottom; by analogy we are 
therefore led to suppose that in the Eocene marine Fauna they are only indicative of some 
such local peculiarities. Indeed, most of the Corals of the London Clay belong to Polypi 
nearly allied to species which are now found in very deep water, and seem to be particularly 
organized for living on a loose, muddy, or sandy ground; whereas many of the fossil 
Corals of the Calcaire grossier resemble those which now inhabit rocky shores, and are 
seen very near the surface of the sea. 
The principal localities from which our London Clay Corals have been obtained are, 
Haverstock Hill, Highgate and Holloway, near London; Barton, Sheppy, Bracklesham 
Bay, on the coast of Sussex, and Alum Bay (Isle of Wight); most of the species were 
found by Mr. Bowerbank, Mr. Frederick Edwards, and Mr. Frederick Dixon, to whom 
we are indebted for the specimens figured in this Monograph. 
