THE CORALLIAN ROCKS OF ENGLAND. 373 



In the peninsula of Old Malton, where we get a moderate de- 

 velopment of the ordinary type of Coral Eag, as previously noted 

 in describing the quarries on Peasy Hills, there is a renewal of 

 the upper beds, which, in the district bordering the vale of Pickering, 

 we had lost sight of since leaving Slingsby. This continuity of the 

 Corallian beds on the inner rim skirting the vale is there broken, 

 and we cross over a flat expanse of clay for a mile and a half to the 

 Langton ridge on the other side of the Derwent. 



2. East of the Derwent. — This is the second, and smaller, sec- 

 tion of the Howardian district. It comprises the high land of 

 Langton Wold, the southern ridge of which is continued eastwards 

 in North- Grimston Hill, where the Howardians are buried beneath 

 the chalk. 



In this area the Lower Calcareous Grit presents somewhat similar 

 beds to those seen at the Park Quarry, Castle Howard ; these are 

 well exposed in large quarries at Birdsall, containing the usual 

 fossils. 



Though possessing here no special points of interest, it is of 

 considerable importance as a formation. It spreads out in the 

 neighbourhood of Mount Perrant, whose precipitous sides are due 

 to its presence ; and passing further south, it alone is left, of all the 

 Corallian beds between the Oxford and Kimmeridge Clays, though 

 not immediately thinning out. Indeed, over Acklam it is of con- 

 siderable thickness, not less than 80 feet, and, whether as grit or 

 sandstone, contains abundance of Ammonites cordatus or vertebralis. 

 South, however, of this spot it falls off, and with a gradually 

 diminished thickness we trace it beneath Hanging Grimston, till it 

 finally dies away in the vale of Kirby Underdale, and the two clays 

 unite. Thus we have it proved that the separation of the York- 

 shire basin is not due to denudation, but to non-deposition. 



The higher beds, for which we have to look in general to the 

 northern portion, viz. the Langton Wolds, are displayed in numerous 

 quarries throughout this area. The northern roots of the hills as 

 they spring out of the vale of Pickering contain several quarries, 

 mostly in softish oolite (Coralline oolite), with sometimes a moderate 

 development of Rag at the top. The oolite, taking that at Setting- 

 ton railway-quarry as the type, cannot be exactly brought into 

 relation with the oolites of Malton ; but the fossils indicate a rather 

 high position, though not so high as the Pag. 



Belemnites abbreviatas, Ammonites plicatilis, or Achilles, and A. 

 cordatus, all occur here. This is one of the higher positions where 

 we find the more recognized forms of the A.-cordatus group ; yet 

 there is a variety of A. vertebralis, probably the same as that of 

 Sike Gate, which occurs in the Urchin-beds of N. Grimston, which 

 are certainly within the Florigemma-zone. Nerincea fasciata, Pecten 

 incequwostatus, P. intertextus, Astarte ovata, Pygums Hausmanni 

 are some of the more noteworthy fossils. In the principal lime- 

 quarry the coral beds above are not particularly rich ; but the de- 

 marcation between the oolite and the Kag is well kept up through- 

 out the cuttings between here and the North-Grimston station. This 



