394 LAMPLUGH : EARTH-MOVEMENT IN NORTH-EAST YORKSHIRE. 
The inference to be drawn from these considerations is that there 
was a persistent south-eastward land-border to the Jurassic basin 
somewhere in the region now covered by the Chalk, and that in this 
region the concealed Jurassic strata are likely to continue to decrease 
in thickness as they recede beneath the Chalk, just as they are known 
to do in Kent and the Eastern Midlands. Deep borings in South- 
eastern England have proved that the wedge of pre-Cretaceous 
Secondary rocks thins out entirely before reaching the East Coast 
between Northern Kent and Norfolk, so that Palseozoic formations 
are found in this quarter immediately beneath the Cretaceous strata, 
and at much less depth than in the area beyond the Chalk escarpment. 
How far northward this condition may extend we do not know as yet, 
but it is hardly likely to swing north-westward far enough to catch 
the south-eastern corner of Yorkshire. Nevertheless, it is not probable 
that the thickness of the Jurassic rocks would be formidable in 
an exploratory boring anywhere between the South Holderness coast 
and the w^estern edge of the Wolds. Unfortunately the same cannot 
be postulated for the New Eed rocks (Trias and Permian). These 
are usually absent in the South-east of England, but are likely to be 
very thick under the Wolds and Holderness, judging from the results 
of the Market Weighton and other borings in the low ground bordering 
the upper reaches of the Humber.* In fact these results appear to 
denote that the Market Weighton anticline may itself mark an uplift 
over the deepest part of an infilled Triassic basin, comparable to the 
uplift of the Yorkshire Jurassic basin and of that of the southern 
Weald. But we need a bold and persevering plunge with the boring- 
rods east of the Wolds before we can complete the Mesozoic history of 
the county ; and the plunge should be worth making for the prac- 
tical knowledge it would give us, even though it should yield no results 
of immediate commercial value. If there be a man of means to do 
this for us, he may at least count upon our thanks, should no other 
reward be forthcoming. 
* W. Gibson, " On a Deep Boring near Market Weighton.'* Sum- 
mary of Progress of the Geological Survey for 1917, pp. 42-45; also 
" The Concealed Coalfield of Yorkshire and Nottinghamshire."^ Mem, 
Geol. Surv., 1913 (Selby, Barlow, Carlton, Thome and other borings). 
