62 PROCEEDINGS OF THE COTTESWOLD CLUB 



70^ 



North Side of the Thames and below 

 Lechlade and St John's Weir 



BASIN OF the leach 



The source of the Leach is at Seven Springs, 570 feet 

 above the sea, half-a-mile west of Northleach, and in a 

 small valley composed of Inferior Oolite and Fuller's 

 Earth. The river leaves the Fuller's Earth at Sherborne 

 Lodge, three miles south of Northleach, and flows entirely 

 over the Great Oolite to Coat Mill, immediately below 

 East Leach Martin. At Fyfield it enters and crosses the 

 Cornbrash to Lemhill Copse, its remaining course to a 

 mile east of Lechlade, being over the Oxford Clay, 

 joining the Thames half-a-mile east of St John's Weir. 



From its source to the Thames the Leach falls over 

 300 feet, and conveys to the Thames about 500,000 

 gallons of water per day, and most of this is derived from 

 its source; much of the water from the Great Oolite is lost 

 below Sherborne Lodge, the Fuller's. Earth being probably 

 too deeply seated to throw out the superincumbent or 

 absorbed waters of the overlying Great Oolite and Forest 

 Marble. The Leach drains an area of 30 square miles. 

 Of this amount the Great Oolite occupies Ijj^ square 

 miles ; the Forest Marble nearly 7, and the Cornbrash and 

 Oxford Clay 4/2- 



