100 REPORT—1868. 
true White Lias. As the balance of the Palzontological evidence is in favour 
of these beds being younger than the Trias, they must be considered the 
feebly coralliferous strata of the Rheetic strata, or of the Infralias, or Lower 
Lias, according to the taste of the student of dogmatic systematic geology. 
The deposits containing Avicwa contorta in England, Wales, and Ireland are 
not of that physical and mineralogical character which attends coralliferous 
sediments ; and the assemblage of other organisms is not that which usually 
accompanies coral life. 
A cast of a Montlivaltia was discovered in the Avicula-contorta zone, by 
Charles Moore, F.G.S. ; and it is therefore an interesting fossil ; for, except the 
few Permian specimens, there are no corals known in Great Britain between 
this cast and the Madreporaria of the Carboniferous. 
Throughout Europe the strata containing Avicula contorta are generally 
uncoralliferous ; but the great deposits at Azzarola have an old coral-bank. 
These were the coral-reef areas of the period, just as the Gosau and Mar- 
tigues were the coral-reef areas of the Lower Chalk, and as the Dax and 
Caribbean strata were the coral-reef areas of the Miocene. 
The White Lias of Great Britain and Ireland is a local deposit which is 
intercalated between the beds containing Avicula contorta and those consti- 
tuting the zone of Ammonites planorbis (or its equivalent Ammonite, such as 
A. Burgundie). It is absent on the continent, the Ammonites planorbis (or 
its equivalent deposit) succeeding the beds with Avicula contorta. The White 
Lias is very uncoralliferous ; and I have never seen a perfect specimen of a 
Madreporarian from it. The White Lias of Watchet contains imperfect 
Montlivaltie and stunted conico-cylindrical Thecosmilie. A cast of a The- 
cosmilian from Sparksfield resembles that of a species found in the deposits 
above the White Lias in the zone of Ammonites-planorbis and A. angulatus. 
A large Montlivaltia from the White Lias near Leamington has an ellipti- 
cal calice ; but it is not possible to give it a specific determination. A cast of 
a multiseptate discoidal Montlivaltia is found at Punt Hill, Warwickshire ; it 
resembles that of Montlivaltia Haimei, Chapuis et Dewalque. Corals of this 
type are common in the Ammonites-planorbis beds of the east of France and 
Luxembourg, but they do not appear to have existed in England until the 
zone of Ammonites angulatus. This species, having a range from the east of 
France to the west of England and Ireland, is very variable in its form and 
in some structural details. 
It is evident from an examination of the Mollusca of the White Lias, that 
it was a deposit not likely to have corals located in it. The stunted T'heco- 
smilie and discoid Montlivaltiv have no congeners now existing; but many 
genera of simple corals of tubular form are frequenters of the sea-bottom 
from 100 fathoms to the lowest spring-tide range. 
The coral-fauna of this deposit is unimportant, and even that of the next 
series of beds, those containing Ammonites planorbis, is small; but when the 
strata in which Ammonites angulatus existed was examined, a large and very 
varied assemblage of species, indicating old coral-reefs, as well as deep-water 
conditions, was proved to exist. In South Wales a reef hung on to the 
Mountain-limestone coast; and in the North of Ireland, as well as in the 
Lincolnshire area, sublittoral and deep-water forms flourished. Changes 
occurred in the physical geography of these areas, and an arenaceous series 
of deposits containing Gryphea incurva and Ammonites Bucklandi succeeded 
the Welsh deposits just mentioned, and the deeper sea-beds of the east and 
west. The alteration in the sea-depth due to the lowering of these areas 
produced not only an alteration in the mineralogy of the strata, but great 
