388 LAMPLUGH : EARTH-MOVEMENT IN NORTH-EAST YORKSHIRE. 
local circumstance and a considerable exaggeration of the vertical scale. 
This has been done to some extent, and piecemeal, by Fox-Strangways, 
in a series of plates in his General Memoir on the Jurassic Rocks of 
Yorkshire ;* also on more general lines by Professor P. F. Kendall 
in his Report on the Concealed Coalfield,! in which he illustrates the 
Jurassic wedges and shows their disposition in respect to the Market 
Weighton anticline. 
My further treatment of the subject will be based almost entirely on 
the Survey records to which I have referred. In the diagram, Fig. 1 
(PI. XLIV.), I have plotted the thickness of the strata between the 
several planes, with a vertical exaggeration of 26, on a north-south line 
of about 36 miles running from the coast at Sandsend, west of 
Whitby, to the neighbourhood of Huggate, near Pocklington. The 
line selected is that of Longitude West 0° 40^, but any parallel line 
for several miles eastward or westward would yield nearly the same 
section. 
Most of the Jurassic sediments attain their maximum thickness 
shortly before reaching the northern end of this section and dwindle 
slightly towards its termination, as is shown by the flattening of the 
curves. If the section had been drawn farther westward, to start 
from the coast near the mouth of the Tees, it would have added 6 or 8 
miles to the length shown, and the additional portion would have 
presented a more decided northward contraction from the maximum 
thickness. 
In the diagram, I have plotted the low^est plane — that of the 
Rhsetic — as a level-course, and have adjusted the higher planes to 
the positions they would occupy if the Rhsetic still lay horizontally 
under the whole area. Owing to the much greater thickness of the 
superjacent strata in the north, where the succeeding planes up to the 
Corallian are spaced out in a column of about 2300 feet, as against 
less than 300 feet in the south, this arrangement gives to all the higher 
planes a southward inclination, steadily increasing in amount in upward 
order. But we know that each plane in turn was originally horizontal ; 
* "The Jurassic Rocks of Britain, Vol. I., Yorkshire."- Mem. 
Geol. Surv., 1892. 
f "Royal Commission on Coal Supplies," Appendix III., Final 
Report, 1905, pt. ix. : *' Sub-report on the Concealed Portion of the 
Coalfield of Yorkshire, Derbyshire and Nottinghamshire," pp. 19-24, 
28, and Plate VII., Fig. 4. 
