Dr Mitchell on the Chalk and Flint of Yorkshire. 71 



fied than the chalk in the south. This is very perceptible all 

 the way round Flamborough Head, and onwards to Speeton 

 Sands, and I observed the same thing while passing some quarries 

 near the road side between Scarborough and Bridlington. In 

 these quarries, as well as in parts of the cliffs near Bridlington, 

 were thin strata of earth, between the strata, which is a thing 

 rarely seen in the south. 



In many, indeed in most, of the quarries in the south of 

 England, were it not for the horizontal lines of flint, we should 

 not be led to form any idea of their being stratified, however 

 our knowledge of the formation would lead us to know that it 

 must be so. Frequently the fissures and divisions in the chalk 

 almost obliterate the appearance of horizontal stratification, but 

 all round the chalk cliffs in Yorkshire, the appearance of strati- 

 fication is as decided as it can be, and is as much so as in the 

 limestone in Derbyshire, or oolite in Dorsetshire, Wiltshire, or 

 Gloucestershire. In most places the strata were about two feet 

 in thickness. Under the Speeton cliffs, for the extent of seve- 

 ral hundred yards, the strata of the chalk towards the foot of 

 the cliff^s to the height of twenty feet, and the ledges on the 

 beach extending down to the sea, were of a red colour. This 

 has been attributed with good cause to iron diff*used through it, 

 and colouring it. In another place, for an extent of 500 yards, 

 red chalk was visible at the foot of the chff*, and extending down 

 the beach to the sea. In the Yorkshire chalk, in several places 

 I observed extensive veins of fine calcareous spar, of about a 

 quarter of an inch in breadth. I have never seen similar veins 

 in any of the numberless quarries and cliffs which I have exa- 

 mined in the southern counties. 



Under Speeton there is in one place what has been called con- 

 torted strata of chalk, but I consider that the phenomenon is ex- 

 ceedingly simple. The appearance clearly shews, from some 

 cause or other, that there has been a depression ; and the con- 

 sequence has been, that the strata have sunk down in that part 

 forming bending lines, and some of the chalk between has been 

 thrown .forward to fill up the vacant space so produced. In 

 Burlington Bay there is a similar appearance, only on a smaller 

 scale. 



In Yorkshire the flint differs exceedingly from the flint in 



