CHAPTER V. 



THE OLDEST BOCKS OF ENGLAND. 



THE Oxford district, regarded as a field of geological study, may 

 be extended beyond the drainage of the Upper Thames to the grand 

 line of ancient rocks which runs from Malvern to Bristol. In this 

 area, though in patches of small extent, nearly the whole palaeozoic 

 system is observable ; the whole series of mesozoic strata makes 

 its appearance ; and a portion of the eocene strata comes into view 

 near Reading. Over these regular strata we find, pretty exten- 

 sively spread, a scattering of northern drift; and in several of 

 the vales and plains on the course of the rivers lies a considerable 

 quantity of local drift, mostly gravel and sand, with here and there 

 deposits of peat. There are few minerals of value in the district, 

 except iron ore, but great plenty of building-stone, limestone, glass- 

 sand, and brick-earth. 



Thus within easy distance of Oxford, nearly a complete series 

 of English strata can be well examined, the effects of disturbance 

 and the peculiarities of plutonic eruption considered, and the 

 operation of surface-waters fully worked out. The outlines of land 

 and sea at different epochs, the situation of estuaries, possibly the 

 course of primaeval rivers may be determined, and maps be drawn 

 of the palaeozoic, mesozoic, and cainozoic ages of this part of the 

 world, quite as good in their way as those which Ptolemy con- 

 structed for the Isles of Britain soon after their appearance in the 

 records of Roman story. 



The oldest stratified rocks of England, probably older than any 

 in Wales, perhaps as old as any in Scotland, are found in the 

 Malvern Hills, within two hours' of Oxford. These hills rise from 

 the Valley of the Severn, in a solitary ridge to which there is 

 really nothing very similar in the British Islands; the nearest 

 analogues, by geological position and mineral character, being 

 perhaps the felspathic rock groups of the country about Charnwood 



