of the North Side of the Vale of Pickering, 24? 5 



wholly to the south of the road from Kirby Moorside to Sprox- 

 ton, one mile south of Helmsley. In this clay hill I found no 

 opportunity of searching for fossils, but about a mile further 

 west, where the road crosses a low insulated woody hill, I had 

 the satisfaction of finding, in a broken clay bank, a layer of 

 Ostrea deltoidea in tolerable perfection. This is the fifth ex- 

 ample within my own knowledge of this remarkable fossil be- 

 ing found in the Kimmeridge clay of Yorkshire. Its true po- 

 sition here, as at Heddington and other places in the south of 

 England, is very near the top of the oolitic formation which 

 lies beneath ; and I have no doubt it would be found in several 

 other places, and in greater plenty, if it were carefully sought 

 after. From the hill above mentioned, the Kimmeridge clay 

 turns away toward Malton, and accompanies the eastern 

 boundary of the coralline oolite. 



The Oolitic Rocks rise from out of the Vale of Pickering 

 to the north and to the west. Every one accustomed to prac- 

 tical geological investigation will at once recognize in the long 

 slopes from Hambleton and Oswaldkirk, the Terrace of Rie- 

 vaulx, and the sides of Newton dale, the characters of regular 

 declination. There has been a general mistake respecting the 

 order of succession of the members of the coralline oolite 

 series in this tract of country. It has been generally believed 

 that the uppermost beds of the series are coralline or shelly 

 limestone, such as is seen in the quarries near Scarborough 

 and Malton. But in truth, these oolitic beds are separated 

 from the Kimmeridge clay by a considerable thickness of 

 sandy calcareous and ferruginous beds, containing some fossils 

 analogous to those which lie in the calcareous grit beneath the 

 oolite. 



This fact is evident on either the Gilling or Coxwold road 

 to Helmsley. Oswaldkirk bank on the former road shows 

 oolite under a considerable covering of brown sandstone, which 

 continuing beyond Grange is twice covered by detached hills 

 of Kimmeridge clay, but never once exposes the subjacent oolite 

 till we descend to the town of Helmsley (see Plate V. section A). 

 On the Coxwold road, after ascending nearly the whole height 

 of the romantic Wass Bank, we notice the Oxford clay, sur- 

 mounted by mural precipices of calcareous grit, and at the brow 

 of the hill a quarry of coralline oolite covered by a hundred 

 feet of brown and yellow sandstone. This forms the poor 

 heathy moors to the north-west, and continuing N.E. towards 

 Helmsley, presents to that town an escarpment on the declining 

 side which exposes the coralline oolite (see section B). 



Here then we first find indications of a denudation of a very 

 interesting character : a denudation on the dipping edge of the 



strata 



