68 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Nov. 24, 
the same disposition of islands, deep and shallow seas, with remote 
continental spaces and rivers, which now prevails in the coral-areas, 
must be suggested to have existed in the reef-bearing seas of the 
past. The simplicity of the physical conditions, and their continu- 
ance on some one area during all ages, offer an explanation why the 
species and genera of the reefs and deep seas are respectively so re- 
presentative and so evidently formed upon one definite plan. 
There are relations, which can only be hinted at in this communi- 
cation, between the floras and the reptilian and mammalian faunas 
of present coral-areas and those of the past. But the persistence of 
coral-seas, with intervals of deep seas and altered physical conditions, 
during the Liassic, Oolitic, and Cretaceous ages, for instance, may 
explain the singularly defective mammalian fauna, and the charac- 
teristic nature of the reptiles of the strata that contain a flora so re- 
presentative of the Equatorial coral-seas. 
The first land-surface of the Trias in western Europe became, in 
some localities, a sea, and a coral-sea; and before the end of the 
period a great upheaval took place, and a second coral-sea—the re- 
ult of subsidence—was formed. A deep sea in the north and reefs 
in the east of the area followed, after the prolongation of a stationary 
condition of some Triassic surfaces, and after an upheaval of others. 
The reefs of the Lower Lias, so evidently representative of those of 
St. Cassian, were partly contemporaneous with, and partly successive 
to, the deep seas of the Rhetic, which may be regarded as an inter- 
calated series. Europe was a coral-reef.area during the Lower Lias ; 
but great bathymetrical alterations then occurred, and consecutive but 
very closely allied coral faunas appeared onit. The Upper Lias wit- 
nessed the culmination of those alterations which were destructive 
to the reef-faunas. The Oolitic coral-seas which followed had a 
coral fauna closely allied to, and representative of, the Lower Liassic, 
although a great break had occurred in the European area between 
the periods. All the peculiar physical conditions returned, and 
persisted longer on the Continent than in the space now occu- 
pied by England. Coral formation after coral formation appeared 
and gave way to the overwhelming results of altered sea-depth ; but 
throughout the period the character of the fauna altered but little. 
The Neocomian period had a reef-bearing sea in the Central-European 
space, and deep and shallow waters on our area. The physical break 
which occurred between the Coral rag and the Neocomian, witnessed 
the destruction of coral-life over large areas; but the two faunas 
were nevertheless closely allied and representative. 
The Green Sands and White Chalk of the north-west of Europe 
were deposited in increasingly deep seas, whilst the reefs were in full 
force in Central Europe. The affinities of the reef-builders of this age 
were not with the corals of the Gault, but with those of the Neoco- 
mian; and the deep-sea forms were somewhat representative of those 
of the very uncoralliferous deep seas of the Gault. 
The great break betwee the Cretaceous and Nummulitic strata in 
Europe is well appreciated by all geologists; and the opinion of 
Forbes and Austen, that the Tertiary seas of Kurope washed a great 
