1869.] DUNCAN—CORAL FAUNAS OF WESTERN EUROPE. 51 
those adopted by the President. This would be evident, so far as 
concerned Pterodactyles, from a work on Ornithosauria which he had 
just completed, and which would be published in a few days. 
Mr. Ernerine stated that the dolomitic conglomerate in which 
the Thecodont remains occurred near Bristol was distinctly at the 
base of the Keuper of the Bristol area, being beneath the sandstones 
and marls which underlie the Rhetic series. There were no Per- 
mian beds in the area. - He regarded the conglomerates as probably 
equivalent to the Muschelkalk. It was only at one point, near Clifton, 
that the Thecodont remains had been found. 
Prof. Huxtry was pleased to find that there was such a diversity 
of opinion between Mr. Seeley and himself, asit was by discussion of 
opposite views that the truth was to be attained. He accepted Mr. 
Etheridge’s statement as to the age of the Bristol beds. 
2. The Puystcat Grocrapay of WESTERN Europe during the Mxso- 
zoic and Carnozorc periods elucidated by their Cornau Faunas. 
By P. Marrry Duncan, M.B.Lond., F.R.S., Sec.G.8. 
ContTENTSs. 
I. Introduction. VIII. Some Genera of Reef-Faunas, 
II. Deep-sea and Abyssal Corals (ex- ancient and modern. ; 
isting). IX. List of Coral-sea Conditions in 
III. Exceptions. — different Periods ‘ 
IV. Littoral Corals (existing). X. Corals and Coralliferous Deposits, 
V. Reef-making Corals,&c. (existing). in consecutive geological pe- 
VI. Exceptions. riods. . 
VII. Exceptional Relations of the two | XI. Conclusions. 
Faunas. 
I. Lyrropvuctton. 
Tue physical conditions which determine and accompany the ex- 
istence of coral reefs, and the natural history of those vast aggrega- 
tions of species of Madreporaria, have been sedulously and successfully 
studied ever since Darwin and Dana published the facts and theories 
which aroused the scientific world to a sense of their importance to 
geological reasoning. The physical geography of the Indo-Pacific 
and West-Indian seas has been investigated with as much care as 
the zoology of those marine banks which, fashioned by coral polypes, 
form a nidus for the existence of vast numbe-s of Invertebrata, fish, 
and birds. Nothing has been more satisfactorily determined than 
the scheme of the production of reefs, and the system of species- 
grouping that obtains in them. 
The dependence of the coral polypes upon certain definite external 
conditions is as well understood as is that of the myriads of mollusca 
upon the flourishing state of the reef-builders. The dredge * has 
done much to show the characters of the corals in the shallows and 
moderately deep seas of reef areas ; and the species and genera fre- 
quenting them have been distinguished from those peculiar to the 
* The late Mr. Christy gave me the results of his dredgings of Corals between 
Cuba and Jamaica Pourtales, Bull. Mus. Harvard Coll. nos. 6, & 7. 
EQ 
