VOL. XVIII. (2) EXCURSION— TIDENHAM CHASE 107 



thread-like stems, with simple branches, all semi-diaphanous to the eye and 

 softly silky to the touch , with the spores grouped in little red ' ' nucules about 

 the branches ; it lives wholly under water. Several Sedges, all thoroughly 

 characteristic of the heath vegetation and none rare, together with some 

 other closely allied plants, Scirpus setaceus—a. tiny grass-like thing with a 

 little blackish head of flowers near the top of its stem— and a very few stems 

 of Cotton-grass {Eriophorum angusti folium). The last is curiously scarce in 

 West Gloucestershire ; there are many spots in the Forest of Dean that 

 might be expected to have it, but they haven't. The most rem^kable plants 

 besides these were the lesser Lousewort, Pedicularis sylvahca, which this yea.r 

 has flowered so profusely as to give the whole common a red tinge ; the small 

 Marsh Pennywort, Hydrocotyle. with small leaves about the size of a shilling 

 borne on a stalk which springs from the centre of the leaf, the whole plant 

 trailing inconspicuously along the surface of the marsh and bearing tiny 

 simple umbels of reddish flowers. The Purslane, Peplis portida, is frequent ; 

 its foliage, hke so much of the smaller foliage of the marsh ground, is strongly 

 tinged with red ; the white heath Bedstraw, Galium saxahle, is common, 

 and will in a few days, when it opens, be a prominent feature of the vegeta- 

 tion, as is also the Sheep's Sorrel and the Wood Betony. The chief rarity of 

 the neighbourhood is the handsome Rosa pomifem. Three bushes, and three 

 only, are known here ; it is extremely scarce wherever it grows m England— 

 and such places may be counted on the fingers of one hand. [H.J. K.J 



After having studied the botany, the Members went to a place best 

 described as situated below the " a " in the word " Chase '' of Tidenham 

 Chase on the Geological Survey Map, Sheet xxxv. Here there is a deep 

 " swallow-hole." 



The Secretary explained that the district in which they were was geo- 

 logically, of synclinal structure. On the east, in the neighbourhood of Wool- 

 ston, the Old Red Sandstone dipped westwards ; on the west, m the neigh- 

 bourhood of Tintem, eastwards. Above it came the Lower Limestone 

 Shales (which contain rather clayey beds). Carboniferous Limestone and, 

 in two small outliers, clayey shales and gritty beds, which— on the Survey 

 Map— are represented as Millstone- Grit. The gritty beds, especially when 

 weathered, are very receptive of water, and the shaly beds hold it up until 

 there is sufficient quantity or conditions are suitable for it to outflow. 



On the south-west side of the Oakhill Wood outlier— the outlier to the 

 north of that on which they were stood— water was to be seen, and some had 

 been collected and was made use of at the neighbouring saw-mills. 



On the Tidenham Chase outlier a considerable amount of the water 

 available supplies Chase Farm, but it is obvious that the combined yield of 

 the two outliers would be inadequate to rely upon as a safe source of supply 

 for the elevated hamlet of Tutshill. At the place on the edge of the Cha.se 

 located above, water from the gritty and associated clayey beds has found its 

 way down through the limestone. It doubtless helps to swell the volume ot 

 water that issues forth near the place marked by the well in the bank ot tne 

 Wye below " Oakwood," whence is derived the supply which at present 

 supplies Tutshill. A large funnel-shaped depression has been originated at 

 the place in question on the Chase. In wet weather it is partially filled but 

 the water soon disappears. There is a large hollow, apparently a 

 " swallow-hole," in the field near Chase Farm, and another best described 

 as " 4-inch north of the ' e ' in Dennel Hill " on the Geological Survey Map 

 ^ [L.R.] 



TINTERN ABBEY. 



The ride was then resumed, Tintem being the objecti^'e, via Brockweir. 

 The road is of a switchback character, necessitating frequent descent from tne 



