DOGGER SERIES. 317 



stone. They contain the two species of Ostna, etc. ; also Fish- 

 remains. This Ostrea-clay is seen near Appleby Station. 



It is open to question whether the clay occurs in Yorkshire, but 

 doubtless it represents, in part, the Forest Marble of the south- 

 west of England. 



The clay is employed for brick-making at Bedford Purlieus, and New England, 

 near Peterborough. At Bottlebridge, near Overton Longville, some ironstone has 

 been raised on the estate of the Marquis of Huiitly ; but owing to the large amount 

 of waste material, the works were discontinued. The soil is by no means fertile. 



YORKSHIRE. 



Great and Inferior Oolite Series. 



These two Series are divided as follows : — 



Great \ Zones. 



Oolite > Cornbrash. (See p. 307.) 

 Series. ) 



Upper Estuarine Series. 



{Scarborough or Grey Limestone Series. Amiiwnitcs Hiiiitphricsiaiius. 

 Middle Estuarine Series. 

 Millepore Series ,, Sowcrbyi. 



Lower Estuarine Series. 

 Dogger Series ,, MurcIiisoiuE. 



The total thickness of the Inferior Oolite Series, including the 

 Upper Estuarine beds, varies from about 250 to over 600 feet. 



The Oolitic series is best studied on the coast, and in the 

 Hambleton and Howardian hills above Thirsk. 



We owe our knowledge of the strata to the labours of the Rev. George Young 

 and John Bird, ' John Phillips,^ W. H. Hudleston, and C. Fox Strangways, as 

 well as to the collections made by J. Leckenby, W. Reed, Sir Charles Strickland, 

 and others, (See p. 2S5.) 



Dogger Series. 



Resting upon the Alum Shale (Upper Lias) of Yorkshire is the 

 series known as 'Dogger,' a term used by Young and Bird (1822). 



The Dogger is a sandy and oolitic ironstone, but the series is 

 sometimes taken to include not only the Dogger proper, but the 

 grey and yellow sands which underlie it. The total thickness of 

 the series is about 95 feet. 



Mr. Hudleston remarks that it is not certain whether the Dogger 

 (sometimes termed the Scar of Whitby) has received its name from 

 the lines of nodules, so characteristic of it, or from the peculiar 



^ A Geological Survey of the Yorkshire Coast, 1822. 

 2 Geol. Yorkshire, Part I. ; Q. J. xiv. 84. 



