Dr. MantelVs Isle of Wight. 235 



and constituted an island clothed with pine-forests and cycadeous 

 plants. 

 " II. The Wealden Epoch, — The country with its pine-for- 



ests was gradually submerged, and formed the beds of estuaries 



and bays, into which land floods, loaded with sedimentary de- 

 tritus, deposited mud, silt, and sand, abounding in the remains of 

 freshwater mollusks and crustaceans ; in which from occasional 

 irruptions of the sea, were intercalated layers of oysters, and 

 estuarine shells. Bones and teeth of terrestrial reptiles, and of 

 river fishes, with stems and fragments of coniferous wood, were 

 also drifted into the estuaries and bays by the streams and rivers. 

 The gradual subsidence of the sea-bottom covered by these fresh- 



water beds continued, and the sediments acquired an exclusively 

 fluviatile character, till at length the accumulated deposits of a 

 vast river formed an extensive delta, many hundred feet in thick- 

 ness, upon the inferior strata. The imbedded organic remains 

 attest, that throughout this epoch the fauna and flora of the 

 country through which the river flowed, corresponded with those 

 °f the islands and continents of the Oolitic period. 



" III. The Cretaceous Epoch.— The commencement of this 

 era was marked by the subsidence of the entire era now occupied 

 ty the greensand formation, to a depth sufficient to admit of the 

 accumulation of the deep sea deposits, of which the greater part 

 of the cretaceous beds of England, and of the adjacent portion 

 of the European continent, consist. The Wealden sediments 

 were submerged to a great depth, and upon them were deposited 

 sa nds, and argillaceous mud, and calcareous detritus, teeming 

 JMh marine exuvias. But the ocean of the chalk extended far 

 °eyond the limits of the Wealden ; it buried beneath its waters 

 a considerable portion of modern Europe, and its waves reached 

 the New World, and covered part of the continent of North 

 America. This ocean swarmed with numerous forms of marine 

 organisms, belonging in a great measure to species and genera 

 unknown in the earlier, and in the later geological epochs. 1 he 

 Werspersions of freshwater deposits containing terrestrial exuviae 

 "tough inconsiderable, prove that although the delta of the coun- 

 ty of the Iguanodon was submerged in the abyss of the ocean, 

 f.group of islands, or a continent, inhabited by that colossal rep- 

 ^ and its contemporaries, and covered with pine-forests, cyca- 

 de *, and ferns, flourished up to a late period of the cretaceous 

 e poch. 



. ''IV. The Tertiary Epoch.— The bed of the chalk ocean was 

 ^n up, and considerable areas were elevated above the sea. 



t'ther 



pachydermata 

 Europe during this period 



