DAVIS : SECTIONS IN THE LIASSIC AND OOLITIC ROCKS OF YORKSHIRE. 175 
cut through the sandstones and intervening shales in a similar 
manner to those falling to the Esk, and deep dales exhibit the Liassic 
beds in a very instructive manner ; they are Rosedale, Bransdale, 
Farndale and Bilsdale. Further south the streams have deeply 
indented the Coralline Oolites of the Tabular Hills, and carved their 
way through them to the Vale of Pickering beyond, where the streams 
are known as the Rye, Dove and Severn, their combined waters join 
the Derwent a few miles above Malton. 
It is proposed to describe with more or less detail three sections 
which serve to illustrate the whole series of the Liassic and Oolitic 
Rocks which occur in Yorkshire. First : the section exposed in 
Robin Hood's Bay and Peak, which comprise the Lower, Middle, and 
Upper Liassic Strata, the Dogger Beds and the Estuarine Series of 
the Lower Oolites, as high as the Grey Limestone Series. Second : 
the section exposed in the Gristhorpe Cliffs which includes all the 
beds between the Millepore beds of the Middle Estuarine Series, and 
the base of the Coralline Oolites : and third, the Scarborough Castle 
and Hackness sections which expose the Middle Oolites from the 
Cornbrash and Kelloway Rock to the Upper Calcareous Grit? 
i. — Sections at Robin Hood's Bay and Peak. 
The Liassic Beds are well developed in Robin Hood's Bay and 
the Cliff between Blea Wyke and Peak Steel. The oldest beds occur 
only in the scars furthest from the shore, about the middle of the 
Bay (fig. 3). Succeeding beds higher in the series occur in the scars 
of the Bay and in the Cliffs. They give place to the Middle Lias, 
the Marlstone of Prof. Phillips. The Middle Lias consists of two 
parts, the Lower or Sandy Series, well exposed at the North Cheek 
of the Bay and on the west side of the Peak Fault. The Upper part, 
named the Ironstone Series, forms the triangular mass of rock between 
the forks of the Peak Faults ; a complete section is also exposed 
in the cliff at Hawsker Bottom (fig 5). The Upper Lias consists of 
three divisions. The Lowest, a soft grey shale ; the Middle, a hard 
dark shale with doggers : and the Upper, the Alum Shale, with beds 
of hard jet rock at its base. These beds of the Upper Lias may be 
studied in the cliffs west and east of the Fault ; on the west, high 
up in the cliffs at and near the Peak Allum Works ; and on the east, 
