376 J. F. BLAKE AND W. H. HTTDLESTON ON 



types of Lower Calcareous Grit, viz. alternations of hard blue, and 

 soft buff, spongy beds, through a thickness of rather under 40 ft., 

 allowing nothing for dip, which is not very marked in this part of 

 the section ; then occurs the hard blue grit at a, just where the 

 bridle-road passing up the escarpment leaves the main highroad. At 

 a higher level some more soft yellow calcareous grits of rather an 

 earthy character occur, with occasional bands of hard stone ; and 

 rather more than 20 ft. above a are seen some grey sandy lime- 

 stones (at b) which may be called passage-beds. We thus have 

 60 ft. as the thickness of the Lower Calcareous Grit of this locality, 

 though it may very possibly extend below the water-line. 



Above the Lower Calcareous Grit there is in the escarpment, in- 

 cluding some 6 or 7 ft. of passage-beds, just about 100 ft. of Coral- 

 lian limestones, which are divided, though with difficulty, between 

 the Coralline oolite and Coral Eag. 



4. The Coralline Oolite. — The true character of the lower half 

 of this series is not very clear. It consists of harder and softer 

 layers of brownish marly paste with oolitic granules, in this respect 

 somewhat resembling the overlying series, which on palseontological 

 grounds i.-> included with the Rag : Echinobrissus scutatus is the 

 prevailing fossil. There is a small opening towards the base of 

 the escar] . nt under Grimston-Hill House, where the harder beds 

 are extracted for road-stone. Few fossils other than Ech. scutatus 

 were noted here ; but the lower beds contain stray specimens of 

 Chemnitzia heddingtonensis. Towards the middle of this quarry a 

 well-preserved spine of Cidaris Jlortgemma was noted. The latter 

 fact is remarkable, as this urchin is very characteristic of the Rag ; 

 nevertheless a stray specimen has been noted as low as the Trigonia- 

 beds of Sinnington ; whilst in the south of England it is seen below 

 the Rag at Purton, and possibly near Faringdon, but in these cases 

 always sparingly. Its presence in this oolite is of more significance, 

 as it seems to prepare the way for the next series, group 3, between 

 which and this one the line drawn is more or less arbitrary. All 

 that can be said is that a Rag-fauna gradually makes its appearance 

 in the marly oolite, groups 4 and 3, and that in the upper group, 3, 

 this has become most pronounced. We have ventured to draw the 

 line just above a bed of hardish oolite containing numerous speci- 

 mens of Astarte ovata. 



3. The Mamillated- Urchin series. — The best place for studying 

 the development of the Urchin-beds is at the west end of the lower 

 quarry on the south side of the Wharram road, where the lime-kilns 

 are built in some soft drab-coloured marly oolites, said to be very 

 full of Echinobrissus scutatus. The latter probably represent the 

 upper portion of group 4. But between these and the limestone No. 

 2 are some 20-25 feet of beds the representatives of group 3. They 

 are seen to consist of flattened buff-coloured granules in a buff or 

 drab-coloured marl ; and sometimes the marl or paste is devoid, or 

 nearly so, of any granules. They are divided occasionally by beds 

 of hard compact limestone having partially the features of the Rag, 

 and containing a few corals, many spines of Cidaris florigemma, 



