A HISTORY OF BUCKINGHAMSHIRE 



Calamus) is probably native, and the narrow-leaved reed-mace (Typha 

 angustifolia) occurs. The sedges include Carex acuta and C. paniculata, 

 and Sparganium mglectum as well as S. erectum occurs ; and the beautiful 

 meadow crane's-bill (Geranium pratense) is not uncommon, while the 

 willows include Salix caprea, cinerea, triandra, alba, viridis, fragilis, 

 aurita, Smitbiana and purpurea. Near Moulsoe the graceful Carex Pseudo- 

 cyperus grows, and the water-stitchwort (Stellaria aquatica) is rather 

 common. The horned pondweed (Zannichellia palustris) is not unfrequent 

 and the wet pastures are often full of Juncus glaucus. Characteristic 

 plants in addition to those alluded to which grow upon this formation are 

 the ox-tongue (Picris echioides), the marsh stitchwort (Stellaria palustris), 

 the honewort (Sison Amomum), especially where a little gravel is also 

 present, the yellow cress (Roripa palustris], the hemlock (Conium macu- 

 latum), and the black poplar (Populus nigra], which is extensively planted, 

 probably in some cases from the fact that in the early days of our railway 

 system buffers for goods-wagons made of this wood were found to bear 

 the concussion better than almost any other timber. 



THE CORALLINE OOLITE forms in Oxfordshire and Berkshire a con- 

 spicuous ridge stretching from west to east, on which many rare and 

 interesting species grow, but when it reaches Buckinghamshire it thins 

 out and changes its character so greatly as to be scarcely recognizable, 

 and is chiefly represented by a clayey band which may be followed by 

 Worminghall, Oakley, round Muswell Hill, and through Dorton to the 

 base of Quainton Hill, and it may exist in a transitional state at Studley. 

 Instead of the sandy or calcareous soil of a very changeable nature 

 which characterizes the surface soil on the formation in Oxfordshire, 

 there is a more uniform and a much poorer soil on the fragmentary beds 

 of the Coralline Oolite in Buckinghamshire, so that we miss such species 

 as the round-leaved crane's-bill (Geranium rotundifolium), the hybrid 

 poppy (Papaver hybridum), the climbing bindweed (Polygonum dumetorum) 

 and many other species which are found in Berkshire or Oxfordshire. 



THE KIMERIDGE CLAV. In Oxfordshire and Berkshire this forma- 

 tion is quite distinct from the Oxford Clay, since the Coralline Oolite 

 just alluded to keeps them apart, so that we have in those counties plants 

 which are fond of warmer and a more pervious soil abundantly growing 

 on the old coral-reef which rises above the two clay deposits ; but as we 

 have seen in Buckinghamshire, the Coralline Oolite has either entirely 

 thinned out or has been so modified in character as itself to form a clay 

 band. There is nothing over the greater part of north Bucks to divide 

 the great extensive clay deposits from each other, and in some parts, as 

 near Stewkley, the separation of one from the other is described on the 

 Geological Survey as wholly conjectural. 



So far as the formation influences plant distribution we may say 

 that what is true of the Oxford is also true of the Kimeridge Clay. 

 The surface is likewise uninteresting and undiversified ; few rare plants 

 occur ; the absence of springs means that there are no bogs, and such 

 marshes as occur are too sour or rather have the waters too charged with 



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