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BOTANY butterfly (H. chloroleuca), and the helleborines Epipactis latifolia and E. violacea are not infrequent in the northern division, owing apparently to the calcareous nature of the subsoil in many parts. Among plants which seem to occur only on the Chalk are the pasque flower {Anemone Pulsa- tilla), which flourishes on the slopes of the chalk combes near Barton, the blue milk vetch (Astragalus danicus), the horse-shoe vetch (Hippo- crepis comosa), the squinancy wort (Asperula cynanchica), the field rag- wort (Senecio campestris) , the mountain cat's-foot (Antennaria dioica), the Canterbury bell (Campanula glomerata), the felwort (Gent/ana Amarella), and the ground pine (Ajuga Chamapitys). In the list of chalk-favouring plants there are possibly others that are practically limited to the Chalk. The Lower Greensand is responsible for several plants which in its absence would be rare or non-existent in the county. It is a warm and greedy soil, which in parts will grow little more than pines and larches, but where it is mixed with clay a very productive loam is formed, well adapted for market-gardening, as at Biggleswade, Sandy and Potton. The phosphatic nodules known as coprolites are found at the base of the Greensand at Sandy, Shillington, Sutton, Potton and Ampt- hill. Two other seams of coprolites occur in the Gault near Barton, but as they are usually found at some depth it would be difficult to say how far the coprolites affect the character of the flora. Among the plants which have been found only on the Greensand are the silver cinquefoil (Potentilla argentea), the saw-wort (Serratula tinctoria) , the sheep's scabious (Jasione montana), the bilberry (Vaccinium Myrtillus), and the lily of the valley (Convallaria majalis). In the list there are several others that pre- fer the Greensand, and possibly some of them are limited to it. The grasses A ira pracox and A. caryophyllea occur not only on the Greensand, but also on a patch of Tertiary sand in the south of the county. The river Ouse at Bedford is about 90 feet above sea-level. Luton rises from 350 to 450 feet, Dunstable to 483 feet, and Dunstable downs to 799 feet. The northern part of the county is hilly, though the heights rarely exceed 300 feet. In the centre and on the eastern side the county is flat right away into Cambridgeshire, but it can hardly be described as fen country. For the last hundred years, especially, the county has been under very high cultivation, particularly in the market-gardening districts. The most interesting piece of marshland is undoubtedly Flitwick Moor, which is a peat bog on Greensand, associated with the river Flitt, and containing a chalybeate water derived from the ferruginous subsoil in contact with vegetable acids. At Gravenhurst there was formerly an interesting moor where such plants as the marsh arrow-grass (Triglochin palustre) and the marsh helleborine (Epipactis palustris) grew. Mr. C. Crouch reports that the former is still found on what survives of the moor, though the orchid is apparently extinct in the county ; and in referring to such plants as the flea sedge (Carex pulicaris), the butterwort (Pinguicula vulgaris), and the grass of Parnassus (Parnassia palustris), which he found on the dry chalk of the Markham Hills, he 39