374 J. F. BLAKE AND W. H. UUDLESTON ON 



oolite has yielded, besides the usual fossils, such as Nerincea fasciata, 

 Pecten Jibrosus, Astarte ovata, &c, a Belemnite which reminds us 

 very much of B. Owenii, together with Pecten qualicosta, Ojpis Phil- 

 lijpsi, Lucina aliena, Corbicella, &c. 



The main interest, however, of the Corallian beds in this portion 

 of the Howardian Hills certainly centres in those of the age of the 

 Coral Rag and subsequent to it. On the high ground of Langton 

 "VVold, of which North -Grimston Hill is merely a continuation 

 (outlier), the Coral Rag may be said to culminate both as to 

 variety and thickness of development, and also in the richness of 

 its fossil contents. There is no such display of this class of rock 

 elsewhere in England. The type along the northern side, where 

 the Rag is seen to cap the Coralline oolite, is very much the same 

 as has already been described, though with more variety perhaps in 

 the fossils. On the southern slope of the Langton-Grimston ridge, 

 another phase of the Upper Corallian obtains ; and this is so well 

 exemplified in the escarpment and quarries on North- Grimston Hill, 

 that we propose to conclude with a detailed accouut of it. 



North Grimston. — At this village the Langton-Grimston ridge is 

 cut through by a transverse valley, thus forming, in conjunction 

 with the escarpment here facing the north, that remarkable salient, 

 North-Grimston Hill. In this way, starting from the village itself, 

 we may trace a continuous sequence from a low position in the 

 Lower Calcareous Grit up into the Kimmeridge Clay of Burdale. 

 Fig. 22 represents the section thus obtained, which is as follows : — 



Elevation on 

 escarpment. 

 Supra- f 1. Cement-stone, or " Lias," maximum proved ft. in. ft. 

 coralline. \ (at quarry) 36 



2. Coral Rag, " North-Grim ston limestone," 



about 40 365 



Coral Rag. «^ 3. Marly Oolites, with an occasional coral band 

 or hard limestone, the mamillated-Urchin 



series, say 25 325 



(4. Drab-coloured marly oolites, becoming very 



Coralline earthy towards the base : full of Echi- 



oolite and J nobrissus scutatus, the equivalent of the 



passage- ] Coralline oolite of other districts, say ... 30 300 



beds. I 4 1 . Passage-beds (not specified in section ; occur 



^ about*) 6 270 



L.C.G. 5. Lower Calcareous Grit down to bed of beck 62 202 



Total thickness of beds in the escarpment. . .163 



The above section is drawn obliquely to the fullest dip of the 

 Coral Rag ; and the exaggeration of the vertical scale produces a 

 certain amount of distortion ; but the actual thicknesses have been 

 estimated on the escarpment, and checked, when practicable, by 

 measurements in the quarries. 



5. The Lower Calcareous Grit possibly commences about the level 

 of the beck (oc) in Grimston village, or on a line of springs a few 

 feet higher. Above this are occasional exposures of the ordinary 



