THE COEALLIAN ROCKS OF ENGLAND. 317 



ence by Dr. Wright, Dr. Lycett, or other writers in the monographs of 

 the Palaeontographical Society. 



One of us has recently, in a communication to the Geologists' 

 Association, endeavoured to a certain extent to supply the want as 

 regards the lower beds ; but the upper portion is now no better 

 known by publication than after the year 1829. It would scarcely 

 be right, however, to omit the mention of Young and Bird, who 

 supplied some interesting details, especially about Grimston and 

 Langton Wold, and who showed themselves careful observers, 

 though unfortunately they mixed the various oolites together. 



The absence also of the published maps and sections of this 

 district by the Geological Survey will render more description and 

 stratigraphical details necessary on our part. 



Even in this one region there are considerable differences of 

 development in its several portions, and it is only by an extended 

 study that we can hope to arrive at the true history of the depo- 

 sition of the beds. It will therefore be most convenient to sub- 

 divide the Yorkshire Corallian area into districts where the develop- 

 ment is fairly similar, and note the gradual change from one into 

 the other. 



For the sake of convenience, we arrange our description under 

 the four following heads : — 



1. The Scarborough District. 



2. The Pickering District. 



3. The Hambleton District. 



4. The Howardian District. 



Although we class all these together under the head of the York- 

 shire Basin, in magnitude and importance they are scarcely less 

 than the whole of each of the other of our subdivisions. 



1. The Scarborough District. 



In this we may include the area between Filey and Brompton on the 

 south and Scarborough and Hackness on the north (see Map, fig. 10). 

 In the eastern portion of this area, excepting the outlier of Scar- 

 borough Castle Hill, the beds have a general dip rather to the west 

 of south ; but at Ayton the strike changes, and the dip becomes 

 one to the S.E. From the sea-coast as far as Brompton the newest 

 beds, as a rule, occupy the lowest and most southerly portion of the 

 district, and, with one trifling exception, the lowest beds occupy 

 the highest ground in the direction of the outcrop. 



As one of us has so lately published a detailed description of the 

 sections to be seen at Filey and Scarborough *, we here need only 

 include what is necessary for reference to the other parts. Having 

 measured these beds independently of each other, and yet agreeing 

 in our description, we submit the section with some confidence, only 

 premising that, as the beds vary in thickness within short distances, 

 some latitude may be allowed on this score. 



* Proceedings of the Geologists' Association, vol. iv. p. 353 et scq. 



