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BYGONES. AGRICULTURE (continued). Contributions to this column will be welcomed and may bo made direct to Mr T. Edwards, Brynteg, Chester, who invites residents and others to send any information relativo to Prestatyn district which they may possess. CARBONIFEROUS Limestone.—Rising ab- ruptly from the drift-covered plain of Pres- tatyn and Meliden, the grey and white lime- stones form a conspicuous escarpement, running southwards through the whole of Flintshire. The abrupt termination of the limestones, and of the line of hills which mark its out- crop at the borders of the maritime plain of Rhyl and Prestatyn, is the result of a number of faults of great size, throwing the limestone far below the level of the sea, and introducing beds of later Carboniferous age. The faults resolve themselves into two principal lines of fracture; the one, which may be called the Prestatyn fault, passes from Prestatyn in a south-westerly direction along the foot of Carreg-y-fran, and shifts the out- crop of the black limestone, from near Pres- tatyn to beyond Meliden the other, which may be called the Vale of Clwyd fault, runs at the foot of Graig-Fawr, by Dyserth Water- fall, below Moel Hiraddug and Cwm mountain, and thence up the whole length of the east side of the Vale of Clwyd. Along the whole of its course, this fault throws down on the west side the limestone and later Carboniferous Beds which underlie the new red sandstone of the Vale of Clwyd, and may be considered one of the principal agents in the production of this remarkable Triassic outlier. From its size and important effect on the physical geography of the region it may take rank as one of the great faults of the British Isles. In the neighbourhood of this fault the lime- stone is smashed up, and much altered, but at a short distance from it, assumes its ordi- nary character, and prevalent south-easterly strike. Following the base from near Dyserth, we find the limestone resting conformably on red conglomerates, and tending to pass down into them by an intermediate stage of impure but fossiliferous limestones, shales, and sandstones of various tints. These beds are exposed in an old quarry between Pentre-bach and Pentre-cwm. The same beds are exposed in several old mining hillocks and small quarries about the south side of Moel Hiraddug, and near marian. They are everywhere characterised by the impurity of the limestone, and its interstrati- fication with shales andcalcerous sandstones and are always associated with a very fine- grained variety of limestone of a pale blue colour, a porcellanous texture, and bearing a soft yellow argillaceous residue on weathering. The most abundant fossils are the Aihyris Royssii and the plant-remains, which appear to belong to the genus Sphsuoptcrix, but are generally tou obscure for recognition. The occurrence of threads of coal, plant- remains, and a coral, in the same bed, is noticeable as indicating the approaching in- vasion of a littoral zoueby oceanic conditions. The great mass of grey and white crys- talline limestones succeed the lower limestone shales. They are distinguished in a general way by their more massive bedding, crystalline texture, and the absence of shale or sandstone. They are exposed for a great thicknes in the sides of Moel Hiraddug, and were largely worked in quarries at the north end of the hill for building and agricultural purposes; and for mixing wt other ingredients for the manufacture of hydraulic cement. The stone contains more than 98 per cent of carbonate of lime, as shown by the following analysis:- Lime 54*664 Magnesia 0'201 Silica 0-905 Alumina 0*010 Potash 0 040 Iron Oxide 0-029 Manganese Oxide 0'018 Humus 0*268 Carbonic acid and water 43*805 100,000 k very pure limestone was formely worked at Bryniau, near Meliden, for use in the Alkali works which stood on the Towyn in Prestatyn. The hill on which the ruins of Dyserth Castle stand is composed of limestone be- longing to this part of the series. A short distance to the east the same beds are inter- sected by a deep ravine enclosed by vertical cliffs. The form of the ravine is determined by the intersection of a fault or strong joint, running S.E. and said to contain copper, with a number of smaller joints running N.W., partly opon and partly filled with calc-spar. The ravine at present is nearly dry, but from its size and depth may not improbably have once formed the site of one of those great springs common in the limestone, similar to the one at Ffynnon Asaph, from which we obtain drinking-water to day. Close to Ffynnon' Asaph is a quarry at Plas-on-bach, fossils are fairly abundant, but from the nature of the beds, very difficult to extract, they lie about 500 feet, above the base of the limestone. Athyris Royasii being remarkably abundant in the lowest beds. Printed and Published by J. T. BURROWS, High.st.,Prestatyn, in the County of Flint.

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