174 MIDLAND UNION PRESIDENT'S ADDRESS. 



We find that Nottiu^;liainshire mainly consists of Triassic and 

 Permian rocks, toj^etber with Oolitic Boulder Clays and Alluvium to 

 a smaller extent, the soil not beiuf^ particularly rich in carbonate of 

 lime. The land species are pretty eijually distributed over these 

 different formations, the sandy districts beiuj^ least prolific of life in 

 these forms, whilst the Magnesian Limestone districts are the richest. 



Of the freshwater species the greater number are to be found in 

 the river valleys, the canals being richest in point of numbers, 

 comparatively few species being found in the ponds above the river 

 levels. Many of our best localities for rare species have disappeared 

 through the march of improvements or trade enterprise ; notably in 

 the case of a pond at Barton, where once was found a rare bivalve 

 {Sphieriitm lacustre) ; there are now none at all, on account of the enlarge- 

 ment of the pond and the consequent destruction of the species. In 

 the same way some of our best botanical hunting grounds ai'e lost to 

 us. Linley Wood is closed ; Bulwell Bogs are gradually disappearing, 

 owing to the encroachments of a railway ; and a pond at Wollaton, 

 in which once grew in profusion the beautiful water violet {Hottonia 

 palustris), has now disappeared, and in its place is a hideous shale 

 heap deposit from a neighbouring colliery. 



Amongst our locally rarer species of shells may be noted : — 



Sphserium lacustre (var. Bronchiana). In Clumber Lake. 



SpliEerium ovale. Canal at Beeston. 



Planorbis lineatus, Highlield House lake (E. J. Lowe), the furthest 



recorded northern locality. 

 Limnasa glutinosa. Found at Beeston Rylands by Mr. Lowe some 



years ago, but not lately found in the district. 

 Ancylus lacustris. At Beeston, on the stems and leaves of aquatic 



plants. 

 Testacella haliotidea. Introduced. Found at Welbeck Abbey. 

 Helix revelata. Stanton-on-the- Wolds (E. J. Lowe). The only recorded 



inland locality, being generally found near the sea coast. 

 Helix fusca. Highfield House (Lowe). Rare. 

 ,, sericea ,, ,, ,, 



„ lapicida. Pleasley Vale and Creswell Crags; also dead speci- 

 mens at Halloughton ; very plentiful on the rocks at Castleton 



and in Dove Dale. 

 Pupa secale. Nottingham Castle (Lowe). 



,, ringens. Highfield House (Lowe). 

 Clausilia laminata. One dead specimen at Pleasley Common ; at 



Matlock and Crich Hill. 

 Achatina acicula. Plentiful in rejectamenta of a small stream at 



Tollert 3n ; also found at Colwick, Attenborough, and Highfield 



House. 

 Cochlicopa tridens. Pleasley Vale, rare ; and plentiful amongst moss at 



Belper. 

 Balia perversa. Rare, Colwick and Highfield House. 

 Vertigo pygmsea. Rare, Widmerpool and Wollaton. 



