390 Glacial Epoch. 



of Carboniferous rocks have travelled from the wide- 

 spread Carboniferous country to the north, that the 

 smaller percentage of Magnesian Limestone fragments 

 must have been derived from the small area immediately 



FIG. 82. 



1. Kotten nodular Magnesian Limestone. 



2. Stiff brown Till with blocks and scratched stones. The 

 largest are of Carboniferous Limestone and Magnesian Lime- 

 stone, from 1 to 1^ yards in diameter, and 1 block 2^ feet of 

 Lammermuir grit. 



3. Sand and loamy beds with scratched stones, rare. 



4. Finely laminated clay. 



north of Sunderland, occupied by that formation for a 

 distance of about 9 or 10 miles, and the decreased pro- 

 portion of Lammermuir rocks have had to travel not 

 less than 70 miles. 



Somewhat further south we find 57 per cent, of Car- 

 boniferous rocks, 32 per cent, of Magnesian Limestone, 

 and only 9 per cent, of Lammermuir grits. 



About half way between Sunderland and Seaham, 

 where on a sea-cliff stiff Boulder-clay or Till lies on the 

 Magnesian Limestone, the latter is covered with 

 glacial groovings which run from NNW. to SSE. and 

 all along the sea-cliffs of this neighbourhood there is a 

 lower Boulder-clay with a very irregular surface, on 

 which there lies sand and gravel, often very much con- 

 torted, which in its turn is overlaid by patches of an 

 upper Boulder-clay. 



