Map No. i. 

 Contoured map of East Northumberland, the numbers denoting heights above sea level. Glacial strice are marked by a circle crossed by a line or an arrow, the arrowhead implying; 

 that the direction is unmistakable. The overflow channels of glacier-dammed lakes are represented by short, thick, black lin?s which are lettered and numbered as explained in the text. 

 The arrows adjacent show the direction of flow of the glacial streams. The thin wavy lines mark some positions of the edges of ice-sheets at the time the glacial lakes were in existence. 



