[348]

Maximum thickness of Each formation, measured in different places.

Cambrian in Merionethshire 7500  

Lingula Flags  5000 Igneous series not estimated in above areas in between about 3000 ft of Ash & Felspathic turfs

Bala & [Caudon] 11500 2nd igneous series as thick as above in middle of Bala beds not estimated in thickness given. These of course are local, but show long lapse of time Pentamerus 2000

Denbighshire flags at base of Wenlock Shale 2000         

Wenlock Shale 1800

Ludlow Rocks? 3500 

Old Red Sandstone Herefordshire 8000    

Carboniferous Limestone 2500      

Coal measures Glamorgan 12000  

Permian Magnesian Limestone (at least     454}  

[do] Marl & Conglomerate of central counties: Warwickshire, Shropshire &c 900} to/

Palæozoic [total of all above figures] 57, 154      

Bunter Sandstone 2500      

Keuper Marl 2000    

Lias 900        

Marlstone 300         

Upper Lias 200        

Lias Sand of Wright 250     

Inferior Oolite 264

Fullers earth 500     

Great Oolite & Forest [Marleh] 500

Cornbrash 50

Oxford Clay 600      

Coral Rag 300         

Kimeridge Clay 900  

Portland Stone 100  

 & Sand 150 

Purbeck 360 

clay 600 bottom unknown}

Weald (unknown) (at least)

Hartings Sand Ashburnham 700 [bottom unknown] 1200 at least

Lower Greensand 800        

Gault 150     

Upper Greensand 170        

Chalk 1000 It is thicker if we band this whole, but no section of the chalk gives this whole   Secondary 8690 this top being always eroded

4560

12190

Secondary 13190    

 

348v]

Plastic clay 100        

London Clay Bracklesham & Bagshot beds 1280 Estimate by Prestwich

Freshwater beds of Eocene 560     

Clay Coralline 55 - 45

Red 40 55

Drift 200       

[Total of above figures] 2235        

Palæozoic 57154 if at 9,000 ft above 13 British miles in Thickness.

(not widely igneous rocks) 13190

Secondary 2235

Tertiary ft in English mile} = 5280

May say nearly 13 & 3/4 of mile in thickness

[calculations]

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