§ 4. THE WEALDEN. 



367 



of modern fluviatile deposits, as explained in a previous 

 Lecture (p. 56). We found the deltas of rivers to consist 

 of clay (or indurated mud), alternating with beds of sand 

 and sandstone (or consolidated sand), and containing leaves, 

 branches, and trunks of trees, fresh-water shells, w^orks of 

 art, bones of man, and of land animals, more or less rolled, 

 — with boulders formed of fragments of rocks, transported 

 by torrents from the hills, or washed out of the banks by 

 the streams. 



Let us now^ suppose that by agencies already explained, 

 a river has disappeared, that the sea also has changed its 

 place, and that the bed of the river and the delta, have 

 become dry land ; that towns and villages have been built 

 upon the consolidated fluviatile sediments, and that the 

 surface is either clothed with turf or forests, or under 

 cultivation. If sections of the strata were exposed, either 

 by natural or artificial means, and the bones of men and 

 animals, with works of art, and remains of plants and shells, 

 were visible in the clay or sandstone, such appearances 

 would excite in us no surprise, because we have made our- 

 selves acquainted with the process by which such deposits 

 are accumulated. And should an inhabitant of the new 

 country express his wonder how brittle shells, and delicate 

 leaves, and bones, had become imbedded in the solid rock ; 



peculiar type, and interpolated amid the rest of the marine formations, 

 as a local fresh-water deposit, of which only very faint traces can be 

 perceived in other parts of England." — Professor John Phillips, Ency. 

 Metropolitana,j>.6%1. Art. Geology. 



" It was not until the appearance of Dr. Mantell's Illustrations of 

 the Geology of Sussex, in 1822, that the full value of the evidence 

 which this district affords was made to appear. In that valuable work 

 the author clearly showed, that the extraordinary remains which he 

 had discovered in the beds of Tilgate Forest, must have originated in 

 a lake or estuary, and have been the produce of a climate much warmer 

 than that which is now enjoyed in England." — Dr.Fitton's Geology of 

 Hastings, p. 14. 



