On the Sand-Pit at High Ongar , Essex. 
83 
The Committee of the Essex County Lunatic Asylum being 
compelled to find further accommodation for their patients, 
purchased a farm at Wickham Bishop, near Witham, exactly 
upon the crest of one of the arcs from the Canterbury centre, 
shown in the map to the above-mentioned paper in the 
‘ Philosophical Magazine,’ and sank a well for water. This 
sinking proved to be a total failure, in consequence of the 
bore passing through a fold in one of the flexures described 
in my paper “ On the Formation of the Biver- and other 
Valleys of the East of England,” and shown as occurring at 
every repetition of the arcs in the hypothetical diagram- 
section, drawn through those spreading outwards from the 
Canterbury centre, given in that paper. 
A description of this bore, accompanied by a section in 
illustration of it, by Mr. W. H. Dalton, F.G.S., appears in 
the ‘ Transactions ’ of the Club for 1881 [loc. cit.). 
The line of the diagram-section in the plate annexed to my 
paper in the Phil. Mag. crosses the arc on which Wickham 
Bishop is situated, about twelve miles W.S.W. of that place, 
viz., at Galley wood. 
In consequence of the very small linear extent of surface 
occupied by them, these folds are mostly concealed; and it is 
only where an excavation, as at Barkway, near Boyston, 
chances to occur over them exactly, or a boring, as at 
Wickham Bishop, happens to hit on one, that evidence of 
their existence can be demonstrated; but the flexure, I 
maintain, occurs continuously along every one of the arcs, 
ex necessitate, as a result of the horizontal displacement 
(caused by the radiating thrustl in which these arcs originated; 
and it was with this conviction that, having occasion in the 
‘ Geological Magazine ’ for 1867 7 to give in connection with 
the Gravels of Essex a section through the ridge at Wickham 
Bishop Trigonometrical Station, which forms one of the 
Canterbury arcs, I explained its origin by reference to my 
above-mentioned paper in Phil. Mag.; and in fig. 9 of the 
7 [“ On the Structure of the Valleys of the Blackwater and the Crouch, 
and of East Essex Gravel, and on the Relations of this Gravel to the 
Denudation of the Weald.” Geol. Mag., vol.iii. (1866), pp.348-854 .—Ed.] 
