THE COKALLIAN ROCKS OF ENGLAND. 351 



though certain peculiar forms, externally not unlike sponges, roughen 

 the surface, as on Scarborough Castle Hill. To the north these same 

 rocks spread out over Arden Moor as hungry grits and sands, every 

 particle of lime having been dissolved away ; and the whole series 

 may be seen in the northern escarpment, in the bed of the road from 

 Hambleton to Yarm, having the same characters as at Roulston Scar. 

 Passing inwards by Byland and Wass, we meet them in a better 

 state of preservation. In Wass Bank about 80 feet may be seen 

 resting on the Oxford Clay. Towards the base we have a rough 

 sandstone with cherty bands and fucoidal (?) stems ; higher up some 

 of the beds are semioolitic, though still calcareous grits. The fauna is 

 scanty ; we noted Pecten ftbrosus, Perna quadrata, Avicula ovcdis, 

 and Myacites recurva. These rocks retain a similar character 

 wherever we catch glimpses of them throughout the long escarpment 

 facing the Gilling erosion ; they gradually sink to lower levels by 

 Ampleforth, where Amm. goliathus, BJiynchonella Thurmanni, and the 

 characteristic Aviculce may be found. Further east they form part 

 of the low ground at the base of Oswaldkirk Bank. (See also fig. 17.) 

 No. 2 is a remarkable series of flaggy oolites, to which we propose 

 to assign the name of " Hambleton Oolites." They correspond in posi- 

 tion topart at least of theLower Limestones of Newtondale,Cropton,&c, 

 and are perhaps continuous with that belt of rock. Their development 

 may be well studied in the Hambleton moors, where they are quar- 

 ried for lime, and where we have had opportunities of proving their 

 position. The group is well seen in Cold-Kirkby quarry, aud in 

 several other quarries on the moor, about the line of section, between 

 the escarpment and Duncombe Park. South of the line of section 

 it begins to lose much of its importance as a distinct body of lime- 

 stone, and has not been traced by us as a separate formation in the 

 Howardian Hills. North of the line of section the Hambleton 

 Oolite appears to increase in thickness ; and in the extreme north- 

 west of the Oxfordian area, where the escarpment is curving round 

 from west to north, it comes to the edge of the cliff as at Kepwick, 

 where nearly 50 feet of thick, massive, and by no means flaggy 

 limestones are quarried for agricultural purposes. Eastward from 

 this point it may be traced, always on high ground, as capping 

 the picturesque and isolated plateau-summits above the village 

 of Hawnby, where the scale and character of the scenery are of a 

 thoroughly Jurassic type. The rock is usually a meagre, gritty, 

 suboolitic limestone, with a tendency in places, especially on Ham- 

 bleton moor, to become an oolite flagstone, the quarries being 

 marked on the 6-inch map as " Slate Quarries." Where the oolitic 

 structure is developed the granules are very small. Fossils are far 

 from numerous, a marked contrast to the true Coralline oolite and 

 Coral Bag. The best localities are Cold Kirkby, where some beds 

 are a congeries of small shells, and Hawnby, where Aviculce and 

 other shells are tolerably abundant. The beds at Kepwick are re- 

 markably poor, considering the amount of rock which is being ex- 

 cavated. The small list our limited time has enabled us to put 

 together is — Belemnites, Ammonites cordatus, Nerincea, Avicula ovalis, 



