62 PROCEEDINGS OF THE GEOLOGICAL SOCIETY, [Nov. 24, 
Lias of England were formed under very variable bathymetrical con- 
ditions ; and deposits of Ammonites, deep-sea corals, and clays follow 
each other. The great coralliferous deposits of Fenny Compton and 
Cherrington were isolated patches on a very uncoralliferous sea- 
bottom. The corals of these deposits. have no affinities with those of 
reef-faunas which preceded them ; and the coral fauna of the zone 
of Ammonites angulatus in Glamorganshire was not represented in 
them, but it was clearly reflected in the assemblage of forms which 
characterized the upper part of the Inferior Oolite. There are no 
evidences of rcefs or of an abundant deep-sea coral area in western 
Europe during these times. During the deposition of the Upper 
Lias and the lower part of the Inferior Oolite, the whole of the area 
appears to have become nearly uncoralliferous. 
The Oolitic Strata. 
There are few geological data more evidently true than the occur- 
rence of successive reefs on the same areas of England and Western 
Europe during the formation of the Oolites. The whole of those dis- 
tricts was occupied by a coral-sea, interspersed with reefs, lagoons, 
and their associated land; and the bathymetrical conditions which 
prevailed resembled those now peculiar to reef-areas. The variations 
in depth on the same portions of the space were very considerable, 
even during the existence of the same groups of associated species ; 
and successive reefs which still form part of the landscape* are 
noticed to be separated by the detritus of former ones, by deep-sea 
deposits, and even by shallow-water formations. Although the 
character of the sea-bottom varied greatly over the whole space con- 
temporaneously and successively, the general characters of a coral- 
sea constantly prevailed; and the identity, resemblance, and repre- 
sentative character of the coral species of the consecutive reefs lead 
to the inference of a continuity of a reef-fauna somewhere or other 
during the whole Oolitic period. The absence of deep seas close to 
continental tracts must be admitted; but the presence of such 
geographical elements as now obtain in the Indo-Pacific may be 
fairly asserted. 
The extent of the coral-sea appears to have reached its maximum 
during the Great Oolite ; and then the conditions which had pre- 
vailed so long, and which had furthered the continuance of the suc- 
cessive reefs, began to alter. 
The indications of reefs diminish very decidedly in the Oxford 
group andits continental equivalents in France, Switzerland, Swebia, 
and Franconia. Moreover our so-called Coral-rag is very poor in spe- 
cies, although it was clearly deposited in a reef-area. Whilst the reefs 
on our area were in existence there do not appear to bave been any 
in Northern and Western France, Eastern Switzerland, or to the east. 
There Trigonia limestones, Cidaris limestones, Ammonites limestores 
and shales appear to have prevailed. But in Western Switzerland 
there were successive reefs which commenced before our horizon of 
* Wright, op. cit. 
