18 



HILLS AND VALES. 



CHAP. 



water shells occur, with bones of mammoth, rhinoceros, hippo- 

 potamus, ox, deer, horse, wolf, boar, &c., just as they have been 



cb 



eg 



Diagram VII. i. Inferior oolite. f. Fuller's -earth rock. go. Great oolite. 

 fm. Forest marble. cb. Cornbrash. o. Oxford clay. eg. Gale. grit. 



co. Coralline oolite. k. Kimmeridge clay. 



found to occur in the Vale of Severn. No additions are now made 

 to these gravel beds by the streams which flow in the ancient 

 channels. 



No gravel corresponding in position to that now mentioned is 

 found to have been brought into the vale of the Upper Thames by 

 the streams which enter from the south side the Rey and the 

 Cole. These streams are so far peculiar, that their origin is not 

 on the sides of the vale of Upper Thames, but begin beyond the 

 next parallel vale (Ock and Thame vale), and pass through the 

 Faringdon ridge before reaching the Thames. Of this more here- 

 after. 



The valley of the Upper Thames is essentially formed in the 

 Oxford clay. It is for a great part of its course only 250 feet above 

 the sea. 



eg co 



Diagram VIII. o. Oxford clay. eg. Calc. grit. co. Coralline oolite, 



k. Kimmeridge clay. p. Portland rock. i. Iron-sand. 



The next ridge, or rather chain of insulated hills, is the lowest 

 of all, its greatest height being reached near Brill, formerly reputed 

 to be 744 feet, but lately corrected, by the more accurate levellings 

 of the Ordnance Survey, to 649 feet. 



Next in height and conspicuous appearance is Shotover Hill, 



