18'65;] JAMIESON LAST CHANGES IN SCOTLAND. 



163 



Pig. 1, — STcetcli-map illustrating the Glacial Phenomena of 

 Scotland. 



Explanation. — The arrows show the directions of the glacial markings ; the thick 

 black lines the cliief ice-sheds, or Knes whence the land-ice flowed dviring the 

 period of the Boulder-earth. The ruled parallel lines show the districts where 

 the Brick-clays and fossiliferous glacial-marine beds seem chiefly to occur. 

 The dotted lines illustrate the distribution of the valley-gravel; the black 

 patches mark the beds of old estuarine mud, or Carse-lands ; and the sites of 

 submerged forests are indicated by a cross ( + )• 



