ON THE 



RIVERS OF THE COTTESWOLD HILLS 



WITHIN THE WATERSHED OF THE THAMES 



AND THEIR IMPORTANCE AS SUPPLY TO THE MAIN RIVER 



AND THE METROPOLIS 



BY 



R. ETHERIDGE 



READ TO THE COTTESWOLD CLUB, FEBRUARY 20th, 1893 



The series of strata comprising the structure of the 

 upper portion of the Thames extends from the line of the 

 Watershed separating the Valley of the Thames from that 

 of the Severn, in places 800 to looo feet above the sea. 

 North of Sevenhampton the divide is between 800 and 

 900, and near Snow Hill 1000* 



The Stratified Rocks occupying this elevated tract of 

 country consist of eight divisions of the Jurassic series, 

 ranging from the Lower Lias to the Portland sands and 

 Limestone. 



The impervious strata occupy nearly 800 square miles, 

 and the pervious series 650 square miles. The retentive 

 or argillaceous rocks thus occupy the larger area, but 

 they contribute little directly to the springs that reach the 

 Thames above Lechlade, or to the purer waters of the 

 Windrush, Hvenlode, or Cherwell, which latter river with 

 the Ray drains an extensive area of nearly 450 square 

 miles. 



* This portion of the drainage area of the Thames is of great importance, having 

 reference to the general geological structure of the eastern and north-eastern watershed; 

 from the several divisions of the Jurassic rocks there is a great supply of pure spring 

 w.iter daily p.issed into the Thames to supply the metropolis. 



D 



