204 DAVIS : SECTIONS IN THE LIASSIC AND OOLITIC ROCKS OF YORKSHIRE 
Avicula inpequivalvis, Sow. 
Modiola bipartita, Sow. 
Modiola pulchra. 
Trigonia paucicostata, Lye. 
Trigonia ruppellensis 
Cardium cognatum, Phil. 
Anatina undulata, Sow. 
A. Kcenigi, Sow. 
A. athleta, Phil. 
A. alligatus, Bean. 
A. Gulielmi, Sow. 
A. Gowerianus, Sow. 
A. lunula, Zeit. 
Belemnites Oweni. 
Resting on the Kelloway Rocks is the Oxford Clay. It is 
difficult to draw a dividing line between the two formations, so 
gradually and imperceptably do they merge one with the other. 
The Oxford Clay at Gristliorpe is a grey sandy shale, and, together 
with sandstone above and below, forms one of the grandest sections 
on the Yorkshire coast. The shale? may be traced along the coast 
eastward to a point less than a mile from Filey Brig, where they may 
seen at the base of the cliff. At the opposite end of Gristliorpe Bay 
the Oxford Clay again makes its appearance in Red Cliff, occupying 
about half the height of the cliff. (Fig. 7.) The thickness along the 
coast varies between 120 and 1 50 feet, but inland it rapidly diminishes 
and in some places is scarcely recognisable. It can however be 
generally identified in association with the calcareous grits above by 
its throwing out the water. 
The Lower Calcareous Grit, as already stated, forms the upper- 
most part of the cliff section exposed at Gristliorpe. Its massive 
structure and the hardness of some of its beds have rendered it one 
of the most important elements in the scenery of this part of the 
country. The bold escarpment of the Derwent valley at Langdale, 
Troutsdale, and Hackness are due to this rock ; and the fine series 
of cliffs between Filey Brig and Cay ton Bay also owe much of their 
grandeur to its protective influence. It consists of a yellow cal- 
careous sandstone, gradually changing downwards to a sandy shale. 
It has probably a maximum of 150 feet in thickness. In the cliff 
north-west of Filey Brig about 80 feet of the Lower Calcareous Grit 
occurs, but further on in the Gristliorpe cliffs the grit is thinner, a 
portion of it having been removed by denudation. At Redcliff in 
Cay ton Bay there is a good section in this rock, but from this point 
the outcrop extends inland to Oliver's Mount ; an outlier of the rock 
