Land-tracts during the Secondary and Tertiary Periods. 277 



to the northward by a continuous shore, formed of deposits 

 which had been land since the close of the secondary period, 

 and closed from any connexion with the North American seas, 

 we have in the Vertebrata of the period most satisfactory evidence 

 of a continuous land-connexion between the American and the 

 Europeo-Asiatic continents. Associated in the same bed at 

 Kyson in Suffolk, there have been found remains of the Macacus 

 (Eopithecus), an exclusively eastern genus of monkey, and the 

 Didelphisj an exclusively American form of marsupial. In the 

 nuviatile deposit of Hordle in Hampshire, the remains of a type 

 of crocodile resembling the American form (the cayman) occur ; 

 at the not far distant locality of Bracklesham, in the marine 

 though slightly older portion of the same delta, the true Asiatic 

 gavial has been found ; and in the London clay the true Eastern 

 form of crocodile. In the same nuviatile of Hordle there occurs 

 in the greatest abundance the remains of the peculiar freshwater 

 fish the Lepidosteus, now an exclusively American form ; and 

 associated with these Vertebrata, a land-shell (Helix labyrinthica) 

 now existing only in North America ; and the river in whose 

 deposits these forms occur, discharged into a sea containing 

 mollusca whose affinities, as I have shown, are entirely with the 

 East. Continuing eastward into Asia from the European termi- 

 nation of this Atlantic bridge, by following the line of secondary 

 formations, which extend through Northern Europe and Western 

 Asia uncovered by any eocene deposits (they having been already 

 traced as far east as the Aral Sea), we perceive the wide stretch 

 of land which at the dawn of the tertiary period connected the 

 Asiatic region with America. The dissimilarity between the 

 mollusca of the European and American eocene formations, to 

 which I have already adverted, militates against any hypothesis 

 of a coast-line joining the seas in which such formations were 

 respectively deposited ; and this agrees with what might be in- 

 ferred from the indications afforded by the configuration of the 

 secondary strata which skirt the eocene basins of England, Bel- 

 gium, and France, which is, that the latter countries formed the 

 head of the nummulitic gulf, the coast-line connecting England 

 with the shore of the American eocene sea being on the other 

 side of the land thus closing in that gulf. 



The extension of the European continent westward at the 

 dawn of the tertiary period, in the manner 1 have attempted to 

 describe, that is, in the form of a tract cutting off the nummulitic 

 gulf from the Atlantic, is further shown by the circumstance of 

 the European and American fauna becoming more assimilated 

 when they occur in formations which were due to the sediment 

 of one common ocean, the Atlantic. Thus Sir Charles Lyell 



