54 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Noy. 24, 
the littoral corals. The peculiarities of reef, lagoon, and shallow- 
water species, and the relations of the two faunas to each other 
are then explained. The exceptional species are considered, and a 
typical list of genera whose species form existing reefs and contri- 
buted to those of the past is given. The representatives of some of 
the modern genera in old reefs are noticed, and then the essential 
principles of the line of argument are stated. For instance the cor- 
respondency of physical conditions during the deposition of strata 
containing analogous forms, the presence of compound coenenchymal 
species indicating neighbouring reefs, and their absence in places 
where simple or non-ccenenchymal Madreporaria are found, being 
characteristic of deep-sea areas which were remote from coral-seas. 
The physical conditions of the seas of Western Europe from the 
Trias to the present time are considered, and the geographical pecu- 
liarities now witnessed in association with reef and deep-sea areas 
are briefly referred to. 
The details which ought to be comprised in a perfect essay upon 
this subject are so enormous in amount that I have considered it best 
to offer this paper merely as a “ mémoire pour servir;” and itis to be 
hoped that further researches, especially in the deep seas between 
and beyond the remote islands of the Pacific coral-sea, will clear up 
some doubtful points. 
II. Drsp-sea anp AByssaL Corats (existing). 
Many species of Madreporaria flourish at considerable depths in 
the seas of Western Europe. The Mediterranean Sea, the Atlantic 
off the coasts of Spain, France, and Ireland, and the North Sea be- 
tween the Shetlands and the coast of Norway have yielded to the 
dredger simple, dendroid, and bush-shaped stony corals at depths of 
from ten to many hundred fathoms. 
These European species have representatives in the deep seas off 
long lines of continent in many parts of the world. Such forms are 
sparsely distributed off the western and south-eastern coasts of Africa, 
the northern sea-board of the United States, and the west coast of 
the Isthmus of Panama, and they have been met with in the North 
China Sea and off the coasts of New Zealand and South Australia. 
There is a close resemblance in shape and in minute construction 
amongst these deep-sea corals. Some of the species have great ranges 
in depth and in area, whilst others are restricted to certain spots. 
They are never found constituting coral reefs; and but few of the 
genera to which they belong have contributed forms to the faunas 
of those aggregations of Madreporaria, or to those of the shallow 
waters in and about them. 
The deep-sea corals are not distributed universally over the sea- 
bottom. Some places are not coralliferous, and others are crowded 
with individuals of all sizes of one or more species. All of them 
are restricted to those portions of the sea-bottom which are remote 
from the entrance of large rivers, and from flat muddy shores, and 
which are not in the line of rolling pebbles, where conglomerates 
can form, or of such sediments as would constantly cover the polypes 
