Kendall : The Concealed Coalfields of Yorkshire, etc. 235 



When examination is made of the rocks adjacent to the 

 Chalk Wolds, however, it is found that exactly in line with the 

 anticlinal axis of the Wharfe there is found the most remarkable 

 gfap in the whole geological succession of Yorkshire, the Chalk 

 rests directly upon the Lower Lias. In other words, strata 

 which in other parts of Yorkshire attain an aggregate thickness 

 of close upon three thousand feet are here wholly unrepresented. 



A study of the country north and south of this line shows 

 the manner of disappearance of this great mass of deposits. 

 Some dwindle away to nothing, by mere default of deposition, 

 which might be ascribed to the elevation of the area as dry land 

 at a particular period. Some were clearly wasted away by 

 contemporaneous shallowing and scouring, and a third portion 

 was removed by uplift and erosion of the area during the 

 intervals between different periods of deposition. There is 

 evidence of relative upward movement, repeated at intervals 

 throughout the whole Jurassic (Liassic and Oolitic) period and 

 continued into Cretaceous times. 



This is a clear case of persistent folding, and as it occurs in 

 direct alignment with the anticline which defines the northern 

 edge of the coalfield I feel justified in projecting the boundary 

 eastward under the newer rocks. The unconformity of the 

 Chalk upon the Lias was proved as far east as Huggate in the 

 year 1829, but I have not carried the margin of the Coal basin 

 further than the foot of the Wold escarpment, as I think it 

 probably meets there another line of deep-seated disturbance 

 wiiich forms the eastern boundary. 



The Eastern Boundary. — This boundary of the coalfield is 

 not nearly so easy of definition as those already dealt with, 

 there is no outcrop of ancient rocks to aid, nor are there at 

 present any borings of sufficient depth to throw a clear light on 

 this obscure problem. 



The chief evidence is found in an anticlinal fold in East 

 Lincolnshire, which was discovered by the evidence of two 

 boreholes subsequently to the completion of the geological 

 survey of the district. This anticline which affects the Chalk 

 and Lower Cretaceous rocks, runs in a north-westerly direction 

 from the neighbourhood of the Wash through Willoughby and 

 Alford up to Louth, beyond which it has not been traced, nor 

 do I think it is traceable as a disturbance of the Chalk. 



The question must now be considered : Is this a posthumous 

 foldrepeated after a long interval of geological time, upon thecrest 

 of a deep-seated fold which had affected the Carboniferous rocks? 



1905 August I. 



