•JO 



THE SEVERN TUNNEL SECTION. 



Shaft No. n. 



Fine Sand and Gravel 



^Yellow Sandstone 

 Trias . . . < Red Marl (very hard) 



CDolomitic Conglomerate 



("Pennant Grit 

 Carboniferous . 5 Lower Coal Measures (Clay and Coal Shales 



^ mixed) 20 



150 



Feet. 

 . 18 

 . 12 

 . G8 

 . 28 

 . 4 



Trias 



Carboniferous 



Shaft No. 4. 



Fine Sand and Gravel 

 /■Yellow Sandstone. 

 5 Red Marl (very hard) 

 (.Dolomitic Conglomerate 

 'Pennant Grit . 



Feet. 



7 

 U 

 05 



4 

 19 



Clay Shaloa, 25 fGct| 

 Coal Shales, 10 „ J 



Lower Coal Measures 



Millstone Grit 



Shales (very hard) .... 

 Limestone and Shales 

 ^Eed Sandstone (hard and close graiued) 



;J5 



11 



fi 



14 



2() 



200 



Bottom TToading (from Sliaft No. 4.) 



YardH 

 / Red Sandstone (same as in bottom of shafts . 40 



Limestone and Shales 90 



Shales 40 



Millstone Grit 40 



(Coal Shales, :!0 yards ) 

 Lower Coal Measures [ciay Shales, 70 ' „ \ ^^^ 



Pennant Grit 1,000 



\ Upper Coal Measures (broken by Fault) . . 400 

 Trias . all beyond the Fault. 



Carboniferous . "< 



" The first foatnro to bo noticed in connection with tlicso 

 excavations is the great variety of strata whicli have been 



