DAVIS : SECTIONS IN THE LIASSIC AND OOLITIC ROCKS OF YORKSHIRE. 189 
attribute to them a thickness of about 80 feet." The Geological 
Survey reckon this an over-estimate, and represent the series as 30 feet 
thick. The beds occur at the foot of the cliff below Peak, extending 
seawards on the shore. The shore sections are completely hidden by 
debris from the oolites, and there is thus very little opportunity to 
study them. They consist of four beds of sandy micaceous shale, 
separated by irregular bands of nodules, the latter containing fossils 
of which A mmonites jurensis is most characteristic. The fauna is a 
mixed one, part of the fossils, such as Distinct reflexa, Venus tenuis, 
Pecten disciformis, Dentalium elongatum, See, are upper Lias forms ; 
others are Oolitic. The beds exhibit the last remnants of Liassic 
life and the first dawning of the Oolitic. 
The Oolites. 
The Peak Cliffs south of Robin Hood's Bay attain a height of 
more than 600 feet, and exhibit a magnificent section not only of 
the Upper Lias Beds but especially those of the Inferior Oolite. The 
two series are brought into juxtaposition by the great fault, with a 
downthrow to the south of 400 fee f . Near the extreme headland, 
the Peak Steel, a second fault branches to the eastwards, and between 
the two is the hard triangular mass of rock of the Ironstone Series 
already described (see fig. 6). A most instructive method of visiting 
these sections is to descend the circuitous footpath from the top of 
the cliffs above Blea Wyke to the Dogger Beds at the base. The 
path, which descends from a position near the Peak Railway Station, 
winds down one of the most beautiful and majestic amphitheatres of 
rocks in the country. The several strata extend in semicircles, and 
form a section of great interest and no little grandeur ; thence 
along the cliff base to the Peak Steel,"and again ascend by the path 
which is immediately over the line of fault. 
The Lower Oolites are developed between Blea Wyke and 
Scarborough, the upper beds forming the lower part of the North 
Cliff, whilst the lowest beds occur at Blea Wyke. The latter offer 
an admirable section, and it is possible to examine every bed ; they 
are more extensively developed here than elsewhere, and between the 
* Yorkshire Lias, p. 19. 
