XX. — On the Strata observed in boring at Mildenhall in Suffolk : extracted 

 from a Letter addressed to W. Someufille, M.D. M.G.S. 



By Sir HENRY BUNBURY, Bart. M.G.S. 



[Read June 14th, 1822.] 

 Dear Sir, 

 As the Geological Society may wish to be informed of every circumstance 

 that tends to verify the stratification in different parts of England, I send you 

 an account of what has been observed in this parish on piercing- with a boring 

 machine to the depth of 270 feet. I will first give a short description of the 

 country where the trial was made. 



A part of the large parish of Mildenhall is fen-land, and belongs to the 

 great Bedford Level. The substrata of the fens are not well ascertained; but 

 I am inclined to believe that the blue clay, provincially termed gault, will be 

 found in most places to lie beneath the peat. The remainder of the parish is 

 upland, and has every where a substratum of chalk, which shows itself here 

 and there even amid the fens. This chalk belongs to the range of that rock 

 which passes from Cambridgeshire across this western part of Suffolk into 

 Norfolk. The chalk contains no layers of flints, though covered by loose 

 flints on its surface. It is generally hard enough to serve for a building-stone, 

 if suffered to remain exposed for some months after being dug to the action 

 of the air and frost. The surface soil varies very much ; a large portion of it 

 consists of a thin but rich sandy loam, while a more extensive tract is buried 

 beneath a blowing sand. In hollows on the surface of the chalk-rock we 

 often find deposits of blue clay, and occasionally of marl ; and in one part of 

 the parish are considerable beds of gravel and flint. The fossil remains are 

 very abundant. We find water-worn alcyonia in flint ; echinites both in chalk 

 and in flint ; palates of fishes in rolled pebbles of chalk amongst the gravel ; 

 many shells, and rarely the stalks of the pentacrinite. 



A merchant of Norwich, who has established a small manufactory for wind- 

 ing silk in this village, hoped, by boring to such a depth as to meet with the 

 water derived from a more elevated district, to obtain an overflowing well suf- 

 ficient to turn a water-wheel ; a similar experiment having been tried suc- 

 cessfully at Cambric'ge. The water is found at the village in common wells, 

 remarkably fine and pure at the depth of from ten to twelve or fifteen feet. 



