In Pen hill we have the whole series about seven hundred feet thick, and notice in succession below the millstone grit, and upper flagstone, and coal, The little limestone. Black chert and plates. The main limestone reduced in thickness. Upper limestone Plates, grits, and coal. .1 Flagstone group Black limestone group The underset limestone. Grits and plates of considerable thickness, but not so thick as above The middle limestone here of considerable thickness. The Simonside limestone. Flagstone and plate.. The Hardrow scar limestone, which ranges from Bishopdale by The lower scar limestone divided by several plate beds. It is evident, therefore, that in an east and west direction the Yoredale series retains so much of a definite character as to afford an ample general standard, to which all the variations on the south and north may be very conveniently compared. In general it is evident that the limestones approximate continually nearer together as we proceed eastward, the intermediate beds growing thinner. G Coverdale.-Descending from Pen hill in a south-eastward direction to Melmerby, we cross the grit of the summit, and below it a series of flagstones, plates, and coal, dipping E. About six hundred feet below the summit, Melmerby Beck falls among beds of chert (partially decomposed to rottenstone) about twelve feet thick; a quarter of a mile to the south, and about six hundred and fifty feet below the summit, is a remarkable quarry of main limestone, resting on twenty-five feet of yellow laminated grits, and seventy-five feet of plate. The limestone is in a singular condition, and as full of vertical and inclined joints, as greenstone rocks often are. The stone is brown and ochry (as usual where it is changing to chert) and crinoidal. It ranges obscurely by some green banks to the north, and holds an indistinct course along the high ground to the head of the dale. Below the plate lies a flaglike bed of impure crinoidal limestone, then twenty feet of solid gritstone, holding spirifera; thin plates and grits follow, and next, about sixteen feet of yellowish gray crinoidal limestone. In the course of two hundred and eighty feet farther descent, the stream crosses other limestones, but the section is not satisfactory. At its junction with the river Cover, limestone in thick beds appears and ranges up Scrafton Beck for one hundred and thirty feet; shewing prismatic structure on a grand scale, especially at the great precipice and remarkable cascade which terminate the cliffs. Beyond, limestone continues in the stream to Great Scrafton, and the total thickness here exposed is taken at one hundred and fifty or one hundred and sixty feet. It is covered by plate. The same blue and gray limestone is seen from Scrafton to Coverdale Abbey, and it is the lowest rock in that part of the valley. In Caldbergh Beck about one hundred feet of this rock is exposed below the road, and above, it supports a series of alternating grits and plates about thirty feet thick, but, as there is a dislocation here, this is probably much too low a measure; the real thickness is doubtless above one hundred feet. On these rests a solid, gray limestone rock, very crinoidal and full of chert nodules. (The joints expand laterally into oval cavities, evidently excavated by water and full of clay.) This limestone is about twenty-five feet thick. Hard shale beds come on above; then grits and plates; then one solid bed of limestone under beds of red, and gray, and dark chert, twenty-five feet in thickness. This chert is often rotten in the central and other parts and dark, smoky gray, striped, dendritical, or purplish within, with hardly any organic remains. It decomposes into a kind of rottenstone. At the top, chert nodules are interspersed. Shales and grits come on above, but no other distinct limestone appears. This upper limestone is traceable along an escarpment generally near to the road from Coverdale to East Witton, being above the road as far as Braithwaite hall, but below the road (which runs in places on its terrace surface) from thence to East Witton. Plates appear below its range, and shales, cherts, and grits 'above. About fifteen feet of limestone are seen, and water breaks out at this level. In East Witton it was sunk through about seven yards in thickness. Plates and grits below. Near East Witton it is much quarried, and appears wholly crinoidal, and full of undulated beds and nodules of chert also crinoidal, and contains productæ and other fossils. The chert is gray (rarely black), often decomposing to brown rottenstone and then discloses multitudes of crinoidal joints. Above is a remarkable parallel bank, reminding us of that formed by the black chert beds of Leyburn and Pen hill. This cherty and crinoidal limestone is the only representative of the Cam or upper scar group, and the occurrence of the variously cherty series above, (as in the north of Wensleydale, and in Swaledale generally, and on the opposite slopes of Pen hill,) and the laminated grits and plates below, leads me to refer it to the main lime; I do so with the more confidence, because in the north-west side of Coverdale both the main lime and underset lime exist together; the latter being certainly continuous with the Parkhead limestone, at the head of the valley, and being much analogous to this limestone of East Witton and Caldbergh. In its course up the valley, on the south-east side, this limestone is not very conspicuous, except in the stream near Hindlethwaite, which descends from the moors in a deep ravine, and other small becks, but it is nowhere deficient, and indeed can be traced from East Witton to Parkhead, except about Great Scrafton. In the middle of Coverdale the blue limestone series rises above the river, and exposes at Gammersgill a flagstone series beneath. The extensive quarries here produce excellent stone, with carbonaceous surfaces, which are often covered with nodules, and vermicular, and ramified markings. The sections at the head of Coverdale are exceedingly interesting with reference to the upper crinoidal limestones, whose diminished and debased character is by them found to prevail through the whole of this valley, especially on the S. E. side. The main lime is seen distinctly encircling the head of the dale in a belt of rocks, and is cut through by the streams which enter the left bank of the Cover. On the opposite side, beneath Great Whernside, this rock is much thinner, but it no where really vanishes from the section. It is usually crinoidal in texture, with undulated nodules of gray chert. On the left (north-west) bank we have, beneath grits and shales, Feet. 50 or 60? of the main or Parkhead limestone. 100 Principally plate. 15 Limestone, gray crinoidal. 40 Plates and flaggy grits, with tessular ironstone bands. On the right side of Coverdale, a stream from between Great and Little Whernside, gives this section. Still nearer the summit and on the right side of Coverdale, a little stream, descending from a surface of pebbly and flaggy grits, and shales, (five hundred feet below Great Whernside) exposes the following beds: Feet. 70 Gritstone and flaggy beds. (20) Parkhead limestone overlapped by the grit at the stream, but appearing on each side. 100 Dark plate. 15 Limestone underset' (in the state of dun' lime), 50 Flagstone and plate. 28 Limestone. Plate, rich in organic remains. South-eastern limits of the Yoredale Series.-Comparing these sections in Coverdale with those formerly given in the adjacent parts of Kettlewell dale, (pp. 30, 31,) it will be seen that both the main lime and underset lime (together making the Cam group) become gradually but completely extinguished on the west front of Great Whernside; not because of any dislocation, but as a law of their original deposition. These limestones have no existence farther to the south-east than the line indicated (p. 19,) as the southern boundary of the Yoredale series. It will also be seen that the gritstones, and plates, and coal, which essentially characterize the Yoredale series, terminate almost completely on the same boundary line as the Cam group; and comparison of the sections of Great Whernside, Parkhead, Starbottom, and Bishopdale head given in pp. |