Table III— Shewing the distribution of the Permeable 



GEOLOGICAL FORMATIONS 



LOWER JURASSIC OR OOLITIC 



The Waters from the drainage of the Lower Jurassic 

 or Oolitic division are conveyed to the Thames by 

 the Thames Head and Ewen Springs, the Churn, 

 Ampney, and Coin rivers above Lechlade and St 

 John's Weir, and by the Leach, Windrush, and Even- 

 lode to Oxford and Wallingford. 



( Middle Lias or Marlst 

 Sands 



Inferior Oolite 

 Great Oolite - 

 Forest Marble 

 Cornbrash 



Fuller's Earth 

 'i. Lower and Upper Lis 



MIDDLE AND UPPER JURASSIC 



Most of the Waters of this division, or the Oxford and 

 Kimmeridge Clays, Corallian Rocks, and Portland 

 and Purbeck are collected by the Ray and Cole, &.c., 

 of the Swindon Basin above Lechlade. 



Lower Calcareous G 

 Coral Rag • 

 Upper Calcareous Gt 

 Portland Oolite - 

 Purbeck 



Oxford Clay - ■ 



*" Kimmeridge Clay 



CRETACEOUS DIVISION 



All the Cretaceous Waters are gathered from the 

 Swindon Basin and conveyed to the Thames above 

 St John's Weir from four divisions, the Lower and 

 Upper Greensand, Chalk, and Gault. 



Lower Greensand 

 Upper Greensand 

 Chalk 



Gault 



I 



Permeable JURASSIC strata drained by the Tributaries to the p 

 Impermeable „ ,, ,, ,, ,, ,, 



Permeable CRETACEOUS strata drained by the Tributaries of \\- ^ 

 Impepmeable „ „ „ ,, ,, 



