XVIII. 



NORTHERN AND SOUTHERN DRIFT. 



461 



the title of ' northern drift ' he describes the pebbly deposit as 

 being but sparingly distributed over the southern portion of the 

 Gloucestershire plain ; it occurs on the flanks of Bredon and Cleeve 

 Hill ; and is composed of materials brought from the north and 

 the east. ' The greater portion of the Cotswold hills is entirely 

 free from drift.' ' The whole table-land of the Cotswolds, from its 

 western escarpment to the neighbourhood of Stow-on-the-Wold, is 

 entirely free from the presence of erratic pebbles.' ' Their western 

 limit may be roughly represented by a line drawn from the southern 

 end of the Vale of Bourton to Cirencester, and on approaching 

 this limit they become so sparingly scattered that their presence 

 is only to be ascertained by carefully searching the ploughed 

 fields/ 



Looking at the distribution of foreign drift in the country under 

 review, we find evidence of abundant currents from the north which 

 brought plenty of gravels on the western side, but no boulder 

 clay ; and plenty of boulder clay with some gravels on the eastern 

 side ; while in the middle space there are traces of currents from the 

 south transporting flints and sarsen stones. 



Yorkshire 



Cumbrian 

 Kocks 



Boulder drift 



WEST. 



Mercian 

 pebbles 



Mercian 

 pebbles j 



Boulder drift 



Flints 



t 



Sarsen 

 Flints f 



I 

 Chalk 



Boulder drift 



EAST. 



range 



