GREENSAND AND PALAEOZOIC ROCKS UNDER LONDON. 



913 



Section of second Well-boring at Crossness (on the south batik of iJie 

 Thames below Black w all) , 1050 yards south of first boring. 





Particulars of Well- 



Depth to top 



Geological Forma- 



Thick- 





section. 



of each bed *. 



tion. 



ness. 



1. 



2. 



Soil 



4- 3-60 ft. 

 + 2'60 



i 



ft. 



Dark brown stiff clay ... 



3. 



Blue silty clay 



- 1-15 



)• Alluvial beds ... 



21 



4. 



5. 

 6. 



7. 



Peat ! 



- 4-98 



- 1140 



- 17-40 



- 35-40 



Quaternary 



18 



Blue silty sand 



River drift gravel 



Very hard stiff blue clay 



8. 



Stiff yellow clay and sand- 

 layers 



- 37-90 







9. 



Hard grey sand, inter- 

 sected with layers 



- 39-40 



' 





10. 



Layers of tenacious clay of 









t 



various hues and shells 



- 47-85 







11. 



Hard sand, with layers 

 of clay 



- 49 90 







12. 



Stiff hard sandy clay . . . 



- 51-15 







13. 



Very hard stiff sandy clay 



- 51-90 







14. 



Dark tenacious sandy clay 



- 56-56 







15. 



Very stiff hard clay 



- 60-15 



Woolwich and | 

 Reading beds J 



47 



16. 

 17. 



Dark green sand 



- 62-15 



- 63-65 



Ditto and shells 



18. 

 19. 



Shell-bed 



- 6424 







Dark green sand, with 





round pebbles of va- 









20. 



rious sizes , 



- 66-15 



- 69-90 







Ditto, but no pebbles ... 



21. 



Green clayey sand 



- 70-40 







22. 



Ditto and pebbles 



- 72-40 







23. 



Ditto and few pebbles... 



- 73-40 







24. 



25. 



Ditto 



- 76-40 







Greenish-grey sand and 





pebbles 



- 77-40 



I Thanet Sands ... 





26. 



27. 



Thanet sand 



- 82-40 



50* 



Layer of flints on top of 



28) 

 29] 



chalk 



- 132-90 



J 



1 Middle and 1 



[ Lower Chalk J 



637£ 



Chalk and few layers of 



flint & rock Chalk-marl 





30. 

 31. 

 32. 



Upper Greensand 



- 764-40 



- 829-40 



"Upper Greensand 

 I Gault 



65 1 



176 



Gault clay 



Gault clay, full of stones, 

 shells, pyrites 





33. 



Top of Red Sandstone 

 and bottom of Gault. 

 Hard red rock-shale. 





^ 





34. 



Micaceous 



- 1004-4 







Very hard grey rock. 



35. 



Micaceous 



-1012-4 







Dark-red argillaceous 



"36. 



shale rock 



-1016-4 



Old Red Sand-] 

 stone or De- f 

 yonian J 



60 



Very hard quartzose red 



37. 



and grey rock 



- 1023-4 





Very hard quartzose 







greenish-grey rock ... 



-1030-9 



1 





38. 



Light-red shale 



-1038-4 







39. 



Greenish-greyish shale . . 



-1040-4 







40. 



Very sharp grey sand, 

 with black grains 



-1044-4 

 -1056-4 



) 





* These depths have reference to Ordnance datum = 12*50 feet below T. H. W. 

 f This should probably be reduced, and the thickness of the Chalk increased. 



Q. J. G. S. No. 136. 3 p 



