ALLUVIUM. 287 



Shells from the Silt of Lewes Levels. 



Marine. Fresh water. 



1. Turbo ulva. 1. Helix planorbis. (Planorbis of 



2. Tellina solidula. Lamarck). 



3. Cardium edule. 2. Helix cornea. (Planorbis cornea 



4. Mactr a List eri. of Lamarck). 



3. Helix stagnalis. (Lymnea of La- 

 marck). 



4. Helix palustris. 



5. ■ limosa. 



6. putris. 



7. tentaculata. 



8. Tuvho fontinalis. 



9. Tellina cornea. (Cyclas cornea of 

 Lamarck). 



The peat consists of the remains of rushes, flags, and the foliage of 

 various kinds of plants that affect a marshy soil ; it occasionally contains 

 the trunks of large trees*. 



The alluvial deposits above described, are clearly of very remote an- 

 tiquity, as is evident from the superficial situation in which ancient coins, 

 &c. have been found. On the west side of Glynd bridge, a paved Roman 

 causeway was discovered lying about three feet beneath the turf, upon a 

 bed of silt twenty feet thick f. And in forming the new road across the 

 levels from Ransconibe to Beddingham, a coin of Domitian was found im- 

 mediately beneath the turf From these circumstances we may infer, that 

 the formation of the levels was antecedent to the Roman advent ; and 

 that since that period, they have not received any material addition. 



They also afford an interesting example of the gradual conversion of 



* " In widening the bed of the Oiise, trees, each containing a load of timber, were dis- 

 covered." CooTc's Topography of Sussex. 



•f- A large brass of Antoninus Pius was found near it. 



