of the District around Colchestpr. 97 



The above list is as complete as I have been able to make 

 it. Of course there are portions of the district that I have 

 not explored, as my engagements have prevented me making 

 long excursions ; but as far as I have gone I think I have 

 searched over the ground somewhat minutely and carefully. 

 It will no doubt be remarked that there is almost an entire 

 absence of species of the genera Fupa, Vertyjo, and Clamilia 

 in my catalogue. I suppose this fact may be accounted for 

 by the deficiency of calcareous strata in the district. All tlie 

 names of shells which appear in the list are inserted after a 

 personal examination of the specimens and localities, and 

 may be relied upon. I have carefully verified every shell 

 named, and to insure correctness in doubtful cases I have 

 had my opinion confirmed by some of the best authorities. 



I cannot leave this subject without calling attention to an 

 extraordinary deposit of land and fresh- water shells, in a 

 fossil condition, in the brickyards at Copford. This Shell 

 Marl was fully described by the late John Brown, F.G.S., in 

 the ' Journal of the Geological Society of London ' for August 

 1852, vol. viii., p. 184. He shows that more than sixty-nine 

 species are there represented, only two of which [Helix in- 

 carnata and H. ruderata) are extinct in this country. 



From a personal examination I can testify to the number 

 of Vertigos, both as regards species and individuals, as well as 

 other rare shells, contained in this deposit. 



M 



