garis as the variety filicaulis); in another, kept permanently wet by the copious springs, we have the golden saxifrage (Chrysosplenium oppositifolium), and even this list does not exhaust the number.
The Greensand stretches out by Heath and Reach to Leighton Buzzard, and is overlapped by the Gault near Fenny Stratford. There are small outlying patches on Muswell Hill and at Brill, and it also caps Quainton Hill. Beds of rich phosphatic coprolites are also found in it occasionally.
The Gault, unlike the Lower Greensand, is a continuous formation which stretches from the Oxfordshire border across Buckinghamshire to the Bedfordshire border near Eaton Bray, and in its progress widens from three miles near Towersey to seven miles on the eastern side. Near the Dunstable downs at Edlesborough a bed of black coprolites is found about fifty feet below the surface of the Gault, which exists usually as a thick mass of pale blue clay, often with greyish-brown phosphatic nodules. The stiff, heavy soil formed by it is usually flat and featureless, resembling the two previous impervious formations in being deficient in interesting species. Those characteristic of the Oxford and Kimeridge Clays are also common to this.
The Upper Greensand overlies the Gault and stretches from Princes Risborough and Henton to about a mile north-east of Buckland, from which place it thins out so as to be not easily traced, but it is to be seen in a brickyard at Eaton Bray. Its junction with the Gault is marked by a series of springs which are thrown out by the impervious nature of the Gault, and near them are situated at short intervals numerous villages, while the copious streams of clear pure water are largely used for the cultivation of water cress, which is sent in great quantity to London and other large towns. One of these springs issues out of the romantic Bledlow Gorge, which furnishes a scene quite unique in the county. The golden saxifrage (Chrysosplenium oppositifolium) grows there, and is a very rare plant in the county.
The Chalk formation is one of the principal strata which come to the surface in the county, not only from the extent of surface which it occupies, but from the conspicuous feature caused by the rather bold northern escarpment of the Lower Chalk with its indented bays, which from a distance give it the appearance of an old coastline, but closer examination reveals the fact that its configuration is not the result of marine but of subaerial denudation, and that in every age it has only been the waves of wind, rain and mist which have surged against it, and carved out indentations which mark its contour in its course from Bledlow to the downs near Eaton Bray. The upper part is formed of a thin but very hard and pinkish bed of Chalk rock resting on other beds of chalk of different degrees of porosity and density, but entirely free from flints. Near the base is a very hard deposit called Totternhoe Stone, and beneath this is a softish white chalk marl, which forms the rising ground between Bledlow, Princes Risborough, etc., and is often under agrarian culture. The abrupt
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