("OLE : SECTIONS AT CAVE AND DEEWTON, 
51 
On the foregoing facts I propose to make a few observations. 
To any one who has studied the Liassic and Oolitic rocks of 
North Yorkshire, an immense difference will be at once apparent 
between them and the rocks disclosed by the railway, pointing to 
the conclusion that they could not all have been deposited under 
similar circumstances, or in the same area. 
1. — With respect to the Lower Lias there is not much to guide 
us. These beds are however better exposed in the southern than in 
in the northern area, and it would seem that as there is no material 
difference, they were deposited under the same geographical 
conditions. 
2. — It is very different with the Middle Lias. In the zone of 
A. spinatus in the northern area occurs the vast deposit of iron ore 
which has given rise to the Cleveland iron trade. Whatever may 
have been the source of this iron, though probably volcanic, it seems 
to have been confined principally to a district between the Tees and 
the Esk ; certainl3' it thins out southwards and no trace of it is found 
south of the anticlinal, sketched by Pi-ofessor Phillips, in the line of 
Garrowby Hill. In Lincolnshire the iron ore of Scunthorpe is 
worked in the lower, A. Bucklandi beds, not in the Middle Lias. 
3. — Then again in the neighbourhood of Cave, though it would 
be hazardous to say that there are no alum shales of the Upper Lias, 
it is certain that there is no jet. This ancient and useful natural 
material for ornament, found in pre-Roman tumuli on the wolds, is 
confined to the A. serpentinus zone of the Upper Lias in the 
neighbourhood of Whitb}^ In the southern area it is wanting, and 
its absence marks a dissimilar condition of affau\s. 
4. — From the Lias to the Kelloway occupies only a short 
distance on the railway, yet the only rock distinctly prominent is the 
Millepore Limestone. The great sandstones of the Lower Oolites, 
which form the Moorlands of North Yorkshire, seem to have died out 
altogether in this southern area; probably they never extended so 
far. They came from the north and were deposited near a shore 
line, and would be cut off altogether from the district under review 
by a submarine ridge in the direction of a line from Garrowby to 
the coast. 
