48 SOME ESSEX WELL-SECTIONS. 



The Little Sampford section is of more local interest, as pointing 

 to an error in the Geological Survey Map (Sheet 47) ; one of those 

 errors that can only be found by such borings, in a tract where the 

 Chalk and the Tertiary beds are covered by a thick mantle of Drift. 



Unless otherwise stated the figures stand for feet. 



[Words in square brackets have been added by the writer.] 



Arkesdon. — Public Well. 1877. 



Made and communicated by Mr. G. Ingold, 

 Water-level 69 feet down. 



Gravel and clay [Boulder Clay] 35 



Chalk 37 



72 



Barking. — Glentiys Bravery. 1889. 



Made and communicated by Messrs. Legrand and Sutcliff. 

 Water-level 1 7 feet down. 



Thickness. Depth, 



ft. in. ft, in. 



Dug well (the rest bored) .. ... 10 o 



[River Drift] gravel 12 o ... 22 o 



Z' Red clay , i o ... 23 o 



I Blue clay 42 o ... 65 o 



I , 1^ rConglomerate, clay, 



[London Clay] -^ S! ^ stone, and shells ... i 6 ... 66 6 



CQ *^ <( Hard rock 5 ... 66 II 



1^- m Sand, clay, and pebbles 3 o ... 69 II 



'"^ ^ l^Rock, flints, and shells O 7 ... 70 6 



/ Loam and shells I 6 ... 72 o 



Sand and shells 6 O ... 78 O 



Blue clay and shells 11 o ... 89 o 



[Woolwich and J Rough pebbles o 6 ... 89 6 



Reading Beds.] \ Mottled clay and sand 16 6 ... 106 o 



Dark clay and sand 2 o ... 108 o 



I Black pebbles o 6 ... 108 6 



(^ Dark sand, clay, and pebbles 17 6 ... 126 o 



r-ru ,<r.A. I ThanetSand 33 o ... 159 O 



[ThanetSand, \ ^^^^.^.^^^ g 6 ... 165 6 



40 feet.] I pij^^^ 6 ___ j55 ^ 



Chalk and flints 154 O ... 320 o 



There is a difficulty in fixing the base of the London Clay, and 



perhaps the lowest bed classed with the Woolwich Series, may 

 belong in part to the Thanet Sand. 



Berden. — [^Bearden on the old Ordnance Ma/>, Sheet 47.] 

 The Hal L 1884. 

 Made and communicated by Mr. Ci. Ingold. 

 Water 122 feet down. 



