60 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Nov. 24, 
tive condition of the coral tracts of England and the rest of western 
Europe. No attention is paid to the existence of land masses. 
Great Britain. Western Europe. 
Reefs. Deep-sea. Littoral. || Reefs. Deep-sea. Littoral. 
ETB riaistheesseeccceas ee Land ve * x 
Rheetic... ...... wae * * x 
S (A. planorbis ...) *R xR *R % 
=~ A. angulatus ...) * * * * * * 
SS LA. Bucklandi...) *R se *R 
Middle Lias ...| ... * * an x 
Upper Lias...... 208 *R ae oe *R 
Inferior Oolite * aaa 3 x 
Middle _,, * pee ihe * 
Coral rag ...... * S00 ne * 
Portland Oolite} *«R an Be % 
Neocomian..... ae * * *R 
Gaulltieeceeeeee * * xR *% *% 
Cenomanian ... * x * % 
Lower Chalk ... * wae 
Upper ,, x : * * 
Hocene ......... was * xR * * 
Oligocene ...... * * * 
Miocene ......... : a x * 
Crag-Pliocene tee * * x x x 
Recent ........ ee * * R * * 
R after an asterisk denotes the paucity of reefs or of deep-sea conditions. 
X. Corars aAnp CoraLtirEerovs Deposits In CONSECUTIVE GEOLOGICAL 
PERIODS. 
The Trias. 
There are no vestiges of coralliferous deposits in the British Trias. 
Formed as a marine deposit, the almost unfossiliferous Triassic sand- 
stones were land-surfaces, whilst there were corresponding tracts 
reaching far away to the south-east, and great coral-reef areas to 
the east of the Vosges. The depth of the marine deposits of the 
Muschelkalk is very great; and some of them contain compound Ma- 
dreporaria and some simple forms. The reef origin of much of the 
dolomite may be inferred; and the general affinities of the corals of 
the Muschelkalk and the St.-Cassian deposits indicate successive reefs 
upon nearly the same area, an elevation of the sediments of the first- 
named strata haying occurred intermediately. 
Rhetic Series. 
The subsidence of portions of the Triassic land surface in Britain 
accompanied the depositioa of the Avicula-contorta beds and the 
White Lias. Some few stunted forms of littoral and deep-sea corals 
existed in the seas of the period in Great Britain. There were no 
reefs in o1r area; nor are there any evidences of such structures in 
Europe, except in the Lombardian Alps and to the north of Savoy. 
The Azzarolan deposits on the Lake of Como* contain abundance 
* Stoppani, op. cit. 
