CHAPTER IV. 



The London Clay continued — Mud Shells and Bubble Shells — 

 Ovoviviparous Pond Snails — Freshwater Limpets — Amber Shells 

 — The Needle Agate Shell — Chrysalis and Close Shells. 



In a little book entitled " Flora Metropolitana," 

 published so long ago as 1836, and long since out 

 of print, will be found an appendix in which the 

 author, the late Mr. Daniel Cooper, gives a list of 

 the land and freshwater shells found in the environs 

 of London. Unfortunately, many of the names 

 employed have become obsolete, or only hold good 

 nowadays as synonyms, so that some little trouble 

 is occasioned in identifying the species referred to; 

 and, as several of the localities mentioned as the 

 sites of ponds and marshes have been long since 

 drained and covered with bricks and mortar, the 

 collector might now search in vain for shells which 

 formerly abounded there. Nevertheless, this list is 

 instructive, as furnishing evidence of the former 

 existence around London of species which may still 

 be looked for in congenial haunts which have not 

 been as jei interfered with. At the same time it 



