NATURAL HISTORY OF CREATION. 91 



Above this bed lie those which have been called the 

 Wealden, from their full development in the Weald of 

 Sussex; and these as incontestably argue that the dry 

 land forming the dirt-bed had next afterwards become 

 the area of brackish estuaries, or lakes partially con- 

 nected with the sea; for the Wealden strata contain 

 exuviae of fresh-water tribes, besides those of the great 

 saurians and chelonia. The area of this estuary com- 

 prehends the whole south-east province of England. A 

 geologist thus confidently narrates the subsequent 

 events : '■' Much calcareous matter was first deposited 

 [in this estuary], and in it were entombed myriads of 

 shells, apparently analogous to those of the vivipara. 

 Then came a thick envelope of sand, sometimes inter- 

 stratified with mud; and, finally, muddy matter pre- 

 vailed. The solid surface beneath the waters would 

 appear to have suffered a long-continued and gradual 

 depression, which was as gradually filled, or nearly so, 

 with transported matter; in the end, however, after a 

 depression of several hundred feet, the sea again entered 

 upon the area, not suddenly or violently — for the 

 Wealden rocks pass gradually into the superincumljcnt 

 cretaceous series — but so quietly, that the mud contain- 

 ing the remains of terrestrial and fresh-w^ater creatures 

 was tranquilly covered up by sands replete with marine 

 exuvia?."* A subsequent depression of the same area, to 

 the depth of at least three hundred fathoms, is believed 

 to have taken place, to admit of the deposition of the 

 cretaceous beds lying above. 



From the scattered way in which remains of the larger 

 terrestrial animals occur in the Wealden, and the inter- 

 mixture of pebbles of the special appearance of those 

 worn in rivers, it is also inferred that the estuary which 

 * Dc la Bcche's " Geological Eescarchcs," p. 344. 



