ON THE BRITISH FOSSIL CORALS. 121 



represented at Brockenhurst. In tlie great reefs of the Custcl-Gomberto 

 district there are the remains of a larger coral-fauna than that which now 

 exists in the Caribbean Sea ; and although a profound Plysch exists between 

 them and the reefs in the Oberburg distiict, indicating great oscillations of 

 the area and vast changes in the life of the time, still the genera which con- 

 tribute so largely to the formation of modern reefs are found represented in 

 abundance in the lowest reefs, which clearly belong to the Nummulitic period. 



Our Eocene corals and those found at Brockenhurst are the stunted off- 

 shoots of the faunas which flourished at Oberburg and in the Vicentine, but 

 nevertheless some of their species are closely allied to those of much later 

 geological date. 



Withoiit the assistance of the labours of Reuss and D'Achiardi zoophytolo- 

 gists could not have imagined that the well-known coral-faunas of the Hala 

 Mountains of Sindh, of the Nummulitic deposits of the Maritime Alps and 

 Switzerland, and of the London and Paris basins were but fractions of a 

 fauna which was probably richer in species than any modern coral tract ; and 

 this welcome aid proves the impropriety of neglecting foreign palaeontology, 

 even when writing reports like the present, and which treat of the produc- 

 tions of the rocks of a small area. The impossibility of comparing with any 

 satisfaction the Nummulitic coral-fauna and that of the Upper Chalk is 

 obvious ; because the NummuHtic fauna, so far as it is known to us, was 

 either a reef or a comparatively shallow-water one, whilst the corals of the 

 Upper Chalk were dwellers in a deep sea, where reef species cannot and 

 could not exist. We must seek to compare the Upper Cretaceous corals with 

 the deep-sea forms of the Nummulitic, but unfortunately they are not yet 

 found*. 



The Lower Cretaceous corals of Great Britain were the contemporaries of 

 the reef-builders of the Gosau and equivalent formations, and thus deep-sea 

 and reef species were contemporaneous, as they are at the present time, but they 

 were separated by wide distances. The comparison of the reef-fauna and that 

 of the deep sea is in this instance as futile as it would be at the present time ; 

 but we may compare the reef-fauna of Gosau with that of the Nummulitic, 

 Oligocene, Miocene, and existing reefs, and not without benefit and good 

 results, for there are persistent species which unite the whole together. 



A comparison may also be instituted between the deep-sea coral-faunas of 

 the Chalk and those which flourished at corresponding depths in the succeed- 

 ing geological epochs. Thus, thanks to Messrs. Wyville Thomson, Carpenter, 

 and Jeffreys, I have been able to assert the extraordinary homologies between 

 the deep-sea Cretaceous corals and those which now exist to the west of these 

 islands. These results are being published by the Zoological Society. The 

 present arrangement of coral genera in and about reefs was foreshadowed as 

 early as the Eocene, and such assemblages of genera existed in those old reefs as 

 would characterize the coral life of atoUs in the Caribbean Sea and in the raised 

 reefs of the Pacific Ocean. The genera Madrepora, Alveopora, Porites, Helias- 

 traa, and Millepora were represented in the Oberburg, and their species con- 

 stitute the bulk of existing reefs. It is important to be thus able, from the 

 labours of MM. Milne-Edwards, J. Haime, and Reuss, to determine the 

 existence of Perforate and Tabulate corals in the earliest tertiaries, for inter- 

 esting links are thus offered to the paleeontologist by which the older and 

 the newer faunas are connected. Such researches diminish the importance 

 of the break between the early Tertiary fauna and the present, and also, to a 



* See P. M. Duncan on a new Coral from the Crag, and on the persistence of Cretaceous 

 types in the deep sea (Quart. Journ. Geol. Soc. sxvii. pp. 369 & 434). 



