Reviews — PhiU'qjs'' Geology of Oxford. 81 



Its contents may conveniently be considered under two general 

 Leadings : Firstly, the Thames Valley, considered in its broad physical 

 features and geographical relations to the rest of England, contribut- 

 ing, by its varied configuration, to render the neighbourhood of 

 Oxford, and that of the Metropolis also, so pleasantly diversified. 

 And, secondly, its Basement-beds, revealing the important fact that 

 our river flows over the upturned edges of ancient strata rich in the 

 relics of organic life, accumulated under more tropical conditions or 

 in a much warmer climate than that at present existing. 



For by consulting a geological map it will readily be seen that the 

 strike of the Mesozoic strata being from the south-west to the north- 

 east, and having a general inclination to the south-east, the beds 

 which successively come to the surface are newer and newer in 

 proportion as we travel in an easterly direction. 



Rising as the Thames does, within a few miles of where the Severn 

 is a navigable river, owing to the elevated position of its watershed, 

 the Cotswold Hills, and flowing as it naturally must over the strike 

 of less and less elevated beds towards the east, it exposes nearly all 

 the Mesozoic strata, and, before it reaches the ocean, the chief part 

 of the Tertiary deposits. 



Replete as these strata are with the evidences of former life, and 

 differing as they do in mineral character, as well as in their organic 

 remains, they afford abundant illustrations of those mutations of the 

 surface which the British area has so frequently undergone in the 

 past, and reveal to us a series of faunas adapted to the successive 

 physical changes it has witnessed. 



It is to the elucidation of such subjects as these that the " Geology 

 of Oxford and the Valley of the Thames " is devoted. 



We may here remark that in dealing with the Oxford district, as a 

 field of geological study, the author goes further westward, beyond 

 the origin of the Thames valley proper, embracing within the scope 

 of his work a review of the whole period of geological time from 

 the oldest rocks of the Malvern range to the latest pre-historic allu- 

 viums. 



Historical notices of the earlier writers who have contributed to the 

 illustration of the geology of the Thames Valley, but more especially 

 of the area around Oxford, occupies the first chapter. 



The next 40 pages are occupied with a sketch of the " Hills and 

 Vales," the Thames and its tributaries forming the main physical 

 features of the district. The author gives a series of diagrams, de- 

 signed to show the effect of a gradual submergence of the land, first 

 to 250 feet below the jDresent level, secondly to a depth of 500 feet, 

 and thirdly to that of 1000 feet. 



At the first, "the Thames Valley would be (must have been) a vast 

 estuary, with a sea-lock up the Kennet Vale ; straits between the 

 chalk hills of Chiltern and Lambourn ; locks right and left up the 

 Thame and the Ock ; straits near Abingdon ; and again locks right 

 and left up the Ray and up the Thames ; narrower and far extended 

 sea-channels up the Severn and the eastern rivers." (p. 44.) 



At the second submergence we should only have "a series of 



YOL. IX. — NO. XCII. 6 



