80 REPORT—1868. 
Judging from the conditions surrounding the existing species and their 
allies, it might be asserted that no very great bathymetrical or climatal 
changes have taken place between the deposit of the Crag and the present 
time. The intervention of a long glacial period is not proved by the study of 
the corals. But doubtless during that period migration to deep water or to 
the south occurred. When the cold period was succeeded by more temperate 
times a return of the fauna took place; and it must be remembered that two 
opportunities at least were thus given for variation in form. 
Fossil Corals from Brockenhurst. 
Lower OLIGocENE. 
Before 1866 no species of corals were known to exist in any beds between 
the top of the Barton series of the Eocene and the base of the “Crag.” I 
published in that year, in the Supplement to the British Fossil Corals, 
Palzontographical Society’s vol. for 1865, descriptions of thirteen species of 
corals from Brockenhurst in Hampshire. The species were, with the exception. 
of two, new to science, and indicated very different external conditions to those 
prevailing at the time of the deposition of the Bracklesham and Barton corals, 
Moreover the two species which had been described from foreign sources 
also indicated a very different state of things from those favourable to the life 
of the tiny simple Turbinolie of the London Clay and of the Barton series. 
The facies of the whole collection was clearly intermediate between the 
Eocene and the Falunian coral-faune. The species were collected from beds 
which are distinctly represented in White Cliff Bay, and which belong to 
the Middle Headon series. 
Overlying freshwater remains (the Lower Headon), it is evident that great 
marine and terrestrial changes had occurred subsequently to the estuarine 
conditions prevailing towards the end of the deposition of the Barton 
series. The genera of the corals discovered at Brockenhurst prove that the 
conditions inseparable from a coral-reef succeeded those favourable to the 
development of estuarine and freshwater species of mollusca. The existing 
species of such genera as Madrepora and Solenastrea are reef-dwellers, and 
Awopora and Litharea are represented in modern reefs by Pocillopora and 
Porites. Such genera as Balanophyllia and Lobopsammia were and are 
dwellers in from 20 to 100 or more fathoms, and are found in the deeper 
water, close to the reefs. A corresponding succession occurs in North Ger- 
many, and deep seams of fossil wood are covered with marine deposits of the 
same relative age as the marine bed at Brockenhurst. Both the marine 
deposits are covered with greater or less depths of sands and gravels. The 
molluscan fauna of Brockenhurst has much in common with those of the 
North German Lower Oligocene deposits superimposed on the fossil-wood 
seams of Magdeburg, Bernsberg, Aschersleben, Egeln, Helmstedt, and Latdorf ; 
and the British as well as the German deposits are moreover the equivalents 
of the “ Tongrien Inférieur.”. - 
The paleontology of the deposits has been sufficiently studied to determine 
the necessity of their separation in classificatory geology from the Eocene 
snd Miocene formations. As yet no satisfactory alliances have been deter- 
mined to exist between the Oligocene coral-fauna of North Germany and that 
of Brockenhurst. But imasmuch as the mollusca are closely allied, there is 
a great probability of the deep-water, oceanic, and reef tracts having been to 
the west of the North German littoral tracts. 
