GEOLOGY. 41 



with but little variation either in character or thickness. 



Beside the main range of moorlands which have been described 

 a narrow terrace of the beds of this series stretches from the 

 Gilling hollow opposite Stonegrave eastward to the Derwent by 

 way of Hovingham, Barton and Malton, bordering the Howardian 

 terrace of Lower Oolite on the north, its beds sloping towards 

 the north-east till they sink into the vale of Pickering. 



(16) The Upper Oolites. Kimmeridge Clay {part of Speeton) 

 Series. — The latest deposits of the Oolitic period which we have 

 in Yorkshire are a series of argillaceous beds which overlie the 

 limestones of the Middle Oolite and which correspond partly 

 to the Kimmeridge Clay which underlies in the South of 

 England the Portland Limestone and partly to the Lower Cre- 

 taceous formation. On the coast of the East Riding we have, 

 rising from beneath the Chalk at Speeton to a height of about 

 200 feet above the high-water mark, a series of beds of dark 

 blue clay, which in some places are much contorted and inter- 

 laminated with nodules of argillaceous ironstone. Within a 

 mile of their first appearance they sink beneath the shore-level 

 and till we reach Filey Brigg the coast line is guarded by massive 

 banks of glacial deposits. Judging from the fossils of these 

 beds the upper portion of them is coeval with the Neocomian 

 or Lower Greensand which in Sussex and Cambridgeshire under- 

 lies the chalk, and the lower part with the Kimmeridge Clay. 

 This lower part stretches round the edge of the beds of the 

 Middle Oolite series to Helmsley and Kirby-moorside and in 

 its inland course lower beds than any of those which are 

 exposed in the coast section are seen, with thin bands of calca- 

 reous gritstone interlaminated amongst the clay and above 

 them layers of Ostrea deltoidea. The beds of this series 

 evidently underlie the whole of the vale of Pickering, which 

 embraces an area of 160 square miles, one half of which belongs 

 to the North Riding. South of the northern edge of the vale 

 they are overlaid by a considerable thickness of glacial beds, but 

 they reappear in several places along the margin of the Wolds. 



Feb. 1888. 



