THE CORALLIAN ROCKS OF ENGLAND. 355 



Helmsley we find it gradually assuming a more coralline form. 

 The exposures referred to consist of about 15 feet of dense creamy 

 limestone, with a few corals and some of the usual fossils, resting on 

 7 feet of Bag with flints. Below this is a coral shell-bed with 

 Thamnastrcea, much Thecosmilia, Rhabdojihyllia, Hinnites velatus, 

 Lima rigida, Lucina, &c. This last is seen to rest on oolite a few 

 feet above the level of the river. Such conditions of the Coral Rag 

 have some relation to the type already noted at Kirkby Moorside, 

 where there is so much " throstler " and " black posts " associated 

 with the ordinary form of Coral Hag. Here, however, the im- 

 purities are siliceous and the fossils well preserved. 



No. 5. The Upper Calcareous Grit. In the above quarry on the 

 York road 3 or 4 feet of this rock may be noted, there rather flaggy 

 and argillaceous. It is merely the base of the formation ; for we can 

 trace it along the road as yellow sandstone and hard blue rock from 

 the level of 210 feet to 280 feet, which, allowing for probable dip, 

 would indicate a thickness of perhaps 30 feet. This, from indica- 

 tions in other portions of the district, we consider to be the general 

 thickness of the formation in the western part of the vale as it 

 gradually passes under the Kimmeridge Clay on the dip-slope. 



In the line of section (fig. 16), the Upper Calcareous Grit comes 

 on a little west of the village of Sproxton : it may there be seen on 

 its outcrop, forming a light soil favourable to the cultivation of 

 roots. Near the village, however, the highest part of which just 

 reaches the 350-feet contour, the country is covered up by a super- 

 ficial deposit (as of fig. 16) of considerable thickness. This is princi- 

 pally a mixture of sand and Eag pebbles ; and further east, where 

 this is not present, there are patches of blue clay, most probably 

 shallow outliers of Kimmeridge Clay. But the Upper Calcareous 

 Grit is again seen in situ on the west side of the alluvial flat in 

 which the river flows opposite Eye House. The same class of rock 

 is again seen on the east side, forming the little precipice on which 

 Eye House is built. It is extremely red and cherty near the sur- 

 face ; this passes steadily under the Kimmeridge Clay, as previously 

 stated. 



One of the chief points of interest in the Hambleton District is to 

 trace the gradual change from the types of the Tabular Eango 

 (which includes the Pickering and Scarborough Districts) to those 

 which prevail in the Howardian Hills, and to note more especially 

 what becomes of the great deposit of the Lower Limestones, and of 

 that Middle Grit which divides them from what is usually known as 

 the Coralline oolite *. Natural causes fortunately have provided us 

 with a section of the Hambleton massive in the escarpment which 

 bounds the Gilling-Coxwold erosion on the north, at the same time 

 that it forms an abrupt termination to the chain. The portion of 

 the escarpment between Ampleforth Beacon and Oswaldkirk is 

 perhaps the most instructive. 



In order to connect this section with the main Hambleton one 



* This will serve to explain the amount of stratigraphy introduced into this 

 portion of the paper. 



2a2 



