396 Scientific Proceedings, Royal Diihlin Society. 



Nearest of all plants to the sea one comes across Salsola Kali. The sand 

 round its roots gives a solution which is slaty blue with thymol blue, denoting 

 the value pH 9-0. This must be corrected for neutral salt error ; the correc- 

 tion is approximate, and reduces the value to pH 8'8. This extract also 

 gives a good pink purple with cresol phthalein, an indicator which shows no 

 trace of colour below pH S"2. The reaction is more intense than the sand 

 encrusted by the sea, which was at pH 8'4. On the clayey sand of the face 

 of Clay Castle, Lotus corniculatus a,nd AnthvUis vulneraria flowered in 

 great profusion, as did also Erodium ciaitariimi, the reaction being 

 pH 8-3. 



The sand dune to the west was at about pH 8'4 on the outer side, where 

 were found Salsola Kali and Arenaria peploides, followed by other plants 

 characteristic of mobile dimes— Mymus arenarius, Jiujphorlia Faralias, 

 Eryngium maritimum. Slightly further in were found Sedum acre, Convolindus 

 Soldanella, and then big patches of Trifoliicm repens and Zotus cornicxdatus 

 at about pH 8-0-7"8, with some T. pratense also. To the east the higher 

 ground was grassy, and the sandy soil was evidently capable of but slight 

 buffer action, bare portions among shingle with Arenaria peploides giving 

 pH 8-0, and the grassy portions pH 7'2-7'8 with Z. corniculatus, Plantago 

 Coronopus, 7'araxacum ojficinale. Salvia Verienaca, Ononis arvensis, Erodium 

 cicutarium L'Her. var. hirtum, etc. Somewhat further inland the higher 

 ground was at pH 8-2, with on the banks Linaria Cymbalaria, Achillea 

 Millefolium, Galium verum, Bellis perennis, and further on occasional bushes 

 of Crataegus OxyacantJia and Ulex europaeus. 



Immediately behind Clay Castle the land slopes northwards to a marshy 

 depression. On the slope the soil has more clay mingled with the sand, and 

 no longer gives any effervescence with hydrochloric acid. Its reaction is 

 pH 6-4, as shown by brom thymol blue and broni cresol purple. Here in 

 the dryer portions Ulex europaeus is plentiful, and in the wet parts Iris 

 Pseuclacorus, Lychnis flos-cucidi, Orchis sp., Eriophorum sp. The low portions, 

 where the bog-cotton occurs, merge into a marsh. Here the reaction was 

 found to be pH 7'2, and Cardamine pratensis was abundant. It may be 

 mentioned that among the gorse on the higher level were several dumps of 

 rubble and a sandy earth atpH 7-6, the ground around being at pH 6-4. On 

 the dumps were Bellis perennis, Anagallis arvensis, Sinapis sp., and Malva 

 sylvcstris, none of which were noticed on the acid soil. 



The marshy region adjoins the road. On proceeding northwards an 

 embankment facing west was largely covered by Ruhus fruticosus, abundant 

 grass with a large white clover, Convolvulus arvensis, and Eqioisehim arvensc. 

 The reaction hereabouts is close to pH 8. The road shortly enters the glen, 



