A HISTORY OF HEREFORDSHIRE high as the Mocktree Shales, graptolites have been chosen for zonal purposes, and since their selection rapid progress has been made in the work of zoning and correlation. These fossils are best preserved in shale-deposits, and therefore it has been chiefly in districts where such a development obtains that the zonal work has been the most actively prosecuted. In Hereford- shire, however, portions of the shale-series are replaced by limestones, in which, from experience, it has been found that graptolite-remains are less frequent. Therefore some difficulty may be anticipated in forwarding this most interesting piece of zonal work in the classic districts of Woolhope, May Hill, and the neighbourhood of the Malverns. Silurian rocks occur in this county in six separate areas — on the north- west between Ludlow and Huntington ; on the east, in the Malvern country and around Aston Ingham (part of the May Hill area), and as inliers at Woolhope, Hagley, and Shucknall Hill. It is now many years since the Government Geological Survey maps of Herefordshire were made. At that time the upper limit of the Silurian was not taken so high up as the ' Fragment-Bed.' Consequently the Silurian rocks occupy a greater area than they are represented to do on the maps, and as that accompanying this essay is based upon them, it follows that on this too their geographical extent is under-represented. Local Details Ludlow-Huntington District. — In a general way this Silurian tract re- sembles that of Woolhope, for the rocks occupy a roughly pear-shaped area. It is not so symmetrical, however, neither do Old Red rocks surround it. They occur along the south-eastern side and are faulted against the Silurian for a space on the north, but the western boundary of the district is a fault — a continuation of that which plays so important a part in the structure of the Church Stretton district. The Silurian Beds, from the May Hill Sandstone to the Temeside Stage, are present in the area, but the Sandstone is only seen in the small section at Pedwardine, and the soft Wenlock Shales — although they floor the Wigmore Valley — are rarely exposed. This is in the main due to the valley-bottom being strewn with Superficial Deposits, but the Shales have been noticed in the bed of the Teme near Burrington.^^ The Wenlock Limestone, being harder than the Wenlock Shales below and the Lower Ludlow Shales above, forms an ill-defined ridge around the lowlands of the Wigmore Valley, and has been quarried and exposed in lanes in several places. The Lower Ludlow Shales, as the name implies, are essentially a shale formation, but near the top, a Httle below the Aymestrey Limestone, are somewhat flaggy beds, locally called ' Pendles.' The Church Quarry at Leintwardine is in these top beds,'" and therefrom — as early as the year 1857 — no less than ten species of star-fish had been procured.* It was here that A. Marston worked with so much success, as the slabs, covered with Pm. Geol. Assoc, iii (1873), p. 125. " Ibid, xviii (1904), p. 491. ^* Ann. y Mag. Nat. Hist, (znd ser.), xx (1857), p. 321 : see also H. Woodward, Quart. Joum. Geol.^Soc. xxi (1865), p. 490. 10
