Page:VCH Worcestershire 1.djvu/71

 BOTANY GENERAL PHYSICAL CHARACTER OF THE COUNTY WITH RELATION TO THE FLORA THE outline of Worcestershire is exceedingly irregular, and not only is this the case, but several detached portions lie outside the main body as islands in neighbouring counties, the largest of these being Dudley in the north and Shipston and Blockley in the south-east. The county may not inaptly be compared in shape to that of a vine-leaf, of which a few fragments have been broken off and scattered near it. And this simile is the more apt because with slight exceptions the whole of the county lies in the watershed of the Severn, which river, running roughly from north to south, divides it into two unequal parts ; and if we place the leaf with the stem down- wards, the venation may roughly represent the tributary streams. Those portions of the county which are not within the basin of the Severn are the extreme north-east, including the north-eastern slopes of the Lickey, where the water runs into the Rea, and so into the Trent ; and the detached portions in the south-east, which are drained by the Evenlode, and are in the valley of the Thames. Another peculiarity may be noticed. Nearly all round, with the exception of the north-west, where the Severn enters the county, the north-east, where the county borders upon Warwickshire, and the south-west, where the Severn leaves it, the margin is higher than the centre ; so we may carry our simile further, and place our vine-leaf in a saucer, parts of the lip of which have been broken away. While the central portion of the county, the wide vale of the Severn, consists of marl overlaid in places with gravelly drift, the higher land towards the margins is mostly of different geological formations. On the west is the long range of the Malvern Hills, rising to the height of 1,394 feet, and composed of plutonic rock with Silurian deposits on their western sides. The county boundary runs for the most part along the summits of these hills, but extends sometimes down the western slopes. Towards Abberley in the north the Malvern range meets the Old Red Sandstone of Herefordshire, on which is situated the district towards Tenbury in the north-west of the county. To the east of Abberley is an extent of New Red Sandstone stretching out to Clent, where the Clent Hills, composed of Permian breccias and sandstones, rise to a height of over i,ooo feet, and are bounded on the north by the coal measures, through which the Silurian rocks of Dudley protrude. Hence 1 33 °