FACTS AND INFERENCES. 281 



their horizontality, must have been disturbed by some mighty agent, 

 elevating the strata in some places, and sinking them in others. 



4. Besides the irregularities appearing in breaks and undulations, 

 there are others which have been produced by the washing away, 

 or removal, of large portions of the upper strata. — Examples of such 

 denudations, as they are called, occur in every part of the coast. 

 Thus, the strata at Filey Bridge must have been covered with beds 

 of oolite, corresponding with those of Seamer and Ay ton; and the 

 strata that break off on the south side of Robin Hood's Bay, must 

 have formerly been connected with the corresponding beds that 

 begin abruptly on the north side ; though the interval now presents a 

 blank, down to the lowest shale. Denudations of this kind appear 

 in the interior, as well as on the shore; particularly along the northern 

 and western fronts of all our ranges of hills. We cannot well sup- 

 pose, that the chalk hills, the oolite hills, or the Cleveland hills, had 

 originally the abrupt faces which they now wear; and no rivers flow 

 round their bases, capable of effecting such a demolition of the upper 

 strata as must have taken place. Similar abrasions appear on the 

 summits and southern slopes of the hills. Thus, the oolite of Picker- 

 ing, instead of advancing to Saltergate Brow, leaves off abruptly a 

 little to the north of Lockton; and the same phenomenon is common 

 in other parts of the oolite range. 



5. The alluvial beds have been deposited after the occurrence 

 of these breaks and denudations. — This is clear from the fact, 

 that the alluvium is observed to till up the breaks of the strata, and 

 smooth the surface. It adapts itself indeed to the larger undulations 

 of the strata, rising as they rise, and falling as they fall; but it 

 conceals the smaller inequalities, and even very considerable breaks, 

 filling up the hollows and chasms. Thus, the ground between Whitby 

 and Dunsley lane is nearly on a level, except at the ravines of Up- 

 gang and Newholm, while the strata beneath repeatedly rise and fall. 



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