CONCLUDING OBSERVATIONS. 301 



in the vicinity of Lewes consist of wood, supposed Juli of the Larch, im- 

 pressions of leaves, seven kinds of Zoophytes, several species of Echinites, 

 upwards of fifty species of univalves and bivalves, and the remains of 

 fishes, and Crustacea. Of these, the Scaphites, Turrilites, Hamites, and 

 the supposed Juli, are the most remarkable. 



7. The Upper and Lower chalk (pp. 139 and 143), form the South 

 Downs ; their characters are too well known to require farther notice. 

 They contain wood ; impressions of supposed vegetable bodies ; nearly 

 thirty different kinds of Zoophytes ; Star fish ; fifteen species of Echinites ; 

 fifty species of univalves and bivalves ; four species of Crustacea ; eighteen 

 or more kinds of fishes ; and the remains of a species of Monitor. 



The strata comprised in the preceding sketch have manifestly, with 

 but few exceptions, been formed by gradual deposition at the bottom of 

 tranquil seas ; the zoophytes and shell-fish having in all probabihty been 

 enveloped, while living in their native beds. It is also evident, that 

 these formations took place at periods sufficiently remote from each other, 

 to allow of the consolidation of the inferior beds, before the upper ones 

 were deposited; the hne of separation being always distinctly marked, 

 and the inhabitants of each formation, essentially differing from those 

 contained in the strata either above, or below it. 



8. The Tertiary formations have been described (p. 250), as lying in a 

 basin, or hoUow of the chalk ; hence it is obvious, that the latter must 

 have suffered considerable destruction subsequently to its consoHdation ; 

 and the immense quantity of roUed chalk flints that occur in the Plastic 

 and London clay, not only confirms that supposition, but also tends to 

 prove that a considerable period must have intervened between the 

 deposition of the chalk, and that of the strata under consideration. The 

 beds comprehended in this division are the Druid sandstone, Plastic clay, 

 and the London clay, and Sandstone. 



The Druid sandstone (p. 253), appears to have anciently extended 

 over a considerable portion of the EngUsh chalk, but now only occurs in the 

 state of large boulders, which in most instances he bare on the surface 

 of the Downs. It is supposed that this sandstone did not form a 



