514 COMPOSITION OF DRIFT CHANGING IN ITS COURSE FROM N.E. TO S.W. 



river, which descends at an angle not greater than that of the Thames above Oxford, 

 wanders for the first few miles after it quits the hills, in a plain of deep, coarse gravel, 

 filled with large bowlders of every variety of trap, derived from the adjacent hills of 

 Cornden and Lindley, and of quartz rocks from the Stiper Stones. This coarse gravel 

 is not merely strewed in the direction of the Onny, but extends also from the depres- 

 sion in which is situated Bishop's Castle, into an upland comb called Prolimoor, filling 

 the cavity between the mountains, above-mentioned, and the Longmynd. All this 

 coarse detritus, however, can be traced up to the north-west, and is therefore one of 

 the proofs alluded to, of the former agency of water ; and hence we may infer, that 

 it was distributed upon the sides of that elevated region, which has been shown to have 

 been peculiarly agitated by volcanic action. Examining the valley of the Onny in the 

 vicinity of Wistantow, a few miles further to the south-east, we find the same materials, 

 but in less quantity and much more finely broken. There, however, the mixture 

 contains in addition fragments of the adjoining mountains of the Longmynd and Caer 

 Caradoc. Arrived in the plain north-east of Ludlow, where the Onny and the Teme 

 unite, and having traversed the ridges of Wenlock limestone and Ludlow rock, we 

 find the accumulations which are so thickly spread over the plain, still further enriched 

 by fragments of these fossiliferous strata. Rounded fragments of all the varieties of 

 trap and Lower Silurian Rocks, including much quartz rock, "are mixed up with 

 fragments of the Upper Silurian Rocks of Wenlock edge and of the Mock tree Forest. 

 Beyond Ludlow and still further to the east, the same materials have been carried 

 only a few miles towards Tenbury, some fragments of the basalt of the Clee Hills being 

 added as soon as the line of drainage has passed that mountain. Further eastward this 

 gravel gradually becomes finer, and below Tenbury we lose all traces of it, the whole 

 of the broken materials thence to the Abberley Hills, having been exclusively derived 

 from the spoil of the adjoining rocks of the coal measures or Old Red Sandstone 1 . 



The manner in which it is supposed, that some of the low alluvial terraces in the 

 valley of the Teme have been formed, will be explained hereafter. 



In describing the matter which has been transported in the same direction as the Teme, 

 it is not to be understood that the mere valley or bed of the river is implied. I allude 

 on the contrary to those heaps of coarse sand, gravel, and clay, which are occasionally 

 spread over hills as well as plains, and which, in some of the hills above Tenbury, are 

 lodged at heights of several hundred feet above the river. These materials are in some 

 parts so arranged, as to convey, like those at Luston, an impression that they were 

 accumulated throughout long periods. The largest bowlders are usually on the surface 

 on the higher grounds south-east of Tenbury. On some of the hills, about one mile 

 and a half south-east of that town, are heaps of this gravel charged with some of the 



1 Townsend, in his Vindication of Moses as an historian, gives similar instances of local drift in the valleys of 

 the Frome and the Avon. Where these streams are separate, the drift belongs to the peculiar region through 

 which the rivers flow ; but after the junction of the two streams, the drift is of a mixed character. 



