OOLITE. 69 



foot of these hills, the traveller crosses a succession of subterraneous 

 rivers.* 



On examining the bed of Hodge beck, where it sinks above 

 Kirkdale church, we find, that the seams, or openings, between the 

 strata, contribute to the absorption of the waters, as well as the ver- 

 tical fissures. These seams, in some parts of the channel, particu- 

 larly in the beds below the oolite, are numerous and open, the strata 

 being thin and slaty; and, the dip of the strata being more rapid than 

 the descent of the channel, the seams successively open towards the 

 current, ready to receive its waters, like the buckets in an over-shot 

 mill-wheel. 



The tendency of the strata in these hills to split vertically, may 

 be supposed to have facilitated the subsidence of the strata, presiuned 

 to have taken place in the vale of Pickering. On the other hand, 

 that subsidence, if such there has been, would have the effect of mul- 

 tiplying and widening the vertical fissures. In a rock near Kirkdale 

 chui'ch, there is a fissure where the appearance of the strata gives 

 sufficient evidence of a dislocation, the strata on the side of the 

 fissure next the valley being lower than the corresponding strata on 

 the opposite side. 



As the principal streams which water the vale of Pickering have 

 not their sources in the oolite hills, but in the hills beyond them, the 

 channel of each of those streams makes a complete section through 

 the oolite and the series of beds connected with it. In such chan- 

 nels, it is not uncommon to find dislocations, or slips, of the strata, 

 to which indeed these channels may owe their origin. For instance, 

 the opening of Newton Dale at Pickering, bears marks of such a dis- 

 location, the oolite on the east side of the stream being higher than 

 the correspoiiding bed on the west. In the channel of the Derwent 



* History of Whitby and tiie Vicinity, II. p. 774. 

 S 



