410
LUDLOW ROCKS OF THE ABBERLEY AND MALVERN HILLS.
to some height above the Silurian deposits as represented in the above vignette. Thealtered characters and dislocations of the strata, produced on the sides of these trappeanhills, will be noticed, after the nature of the intruding rocks has been described; ob-servation being first restricted to the nature and range of the sedimentary deposits ofthe Silurian System.
Ludlow Rocks in the Ahherley Hills. (PL 36, figs. 1 to 4 inclusive.)
Ludlow Rocks in the Ahherley Hills. —This upper formation of the Silurian System occupiesabout one mile of the ridge immediately to the east of the village of Abberley, marked AbberleyHill on the ordnance map. It is cut off upon the south by intrusive rocks, which, forming a knotof still higher elevation, extend about three quarters of a mile to the west, encircling and over-hanging the village of Abberley on the one side, and receding from the Hundred House on theother. Beyond, and to the west of this trap, the Ludlow formation is thrown off in very contortedand dislocated masses, constituting a headland which advances into the coal field of Abberley andPensax. From the western side however, of Abberley Lodge, the formation rises into a distinctmural ridge striking S. 10° W. along the western side of Woodbury Hill; to the south of whichit takes a direction a few degrees east of south to Hill End near Martley, the beds disappearing atKingswood Common. Thence to the gorge where the Teme is deflected through this band, theLudlow rocks are no longer traceable, older Silurian deposits forming the narrow ridge whichseparate the Old Red Sandstone on the west, from the New Red on the east. Throughout its courseon the western slopes of the Abberley Hills, the Ludlow formation offers, on a small scale, the sametriple subdivision as in Shropshire . The upper part, or true Ludlow rock, is the same argillaceousthin-bedded sandstone, containing the gigantic Serpuloules ? longissima, Leptcena lata, Cypricar-dia amygdalina, and other characteristic fossils.
The Aymestry limestone, or central member of the Ludlow formation, is also well defined, andin parts nearly as thick, but never so pure as in Shropshire . Although it has been burnt forlime from the crest of the ridge east of Abberley; the rock is now only extracted for the roads, theadjacent limestone of the Wenlock formation being of very superior quality. The fossils of thisrock are nearly all the same which are found in it in Shropshire , with the exception of the Penta-merus Knightii, which I have not detected. The large Lingula Lewisii is perhaps the most strikingof the organic remains, often retaining, in great perfection, its thin shelly matter. The lowerLudlow rock is also recognised by containing many of the same organic remains as in Shropshire .(See List.)
From the decomposing nature of the sandstone and shale beds, they are locally called “MudStone,” in contradistinction to the hard trappean rocks which occasionally protrude, and are termed“ Jew Stone,” as in the Clee Hills. The total thickness of the Ludlow formation in the Abberleyrange does not exceed 300 feet.