382 JURASSIC CHRONOLOGY. [vol. Ixxviii. 



Thiclcness 

 Sequence of Strata. (approximate) 



in feet. 

 6*. OsTREA-KXORRi Clays : possibly Bed 6 e is a layer 



in these 5 



The foUomng- beds (7-9) are to be seen in the 

 eastern part of the cliff beyond the second 

 fault : — 



7. Umber Bed : umber-coloured clays with a nodular 



band 20 



8. Small Conchoidal Bed : clays with conchoidal 



fracture, breaking into small lumps 40 



9. Ochre Band : a yellowish marly band about 



1 foot thick, seen near the top of the cliff, 

 eastern end, resting on 



Laminated Clays : with light bands of somewhat 



calcareoiis rock. Occasional lumps of pyrites . 50 



Of the following beds, details for 10 and 11 are 

 furnished by Burton Bradstock. There are 

 Inferior Oolite rocks, the Black E-ocks, just out 

 to sea west of the third fault (see later, p. 430). 

 Then part of No. 12 is seen immediately east of 

 the third fault, and the basal part of No. 13 is 

 found with succeeding beds in the cliff west of 

 the first fault : 



10. Belemnite-Clays 15 



. 1 . ^11. Limestone-mass of the Inferior Oolite 16 



Aalenian J 



Yeovilian 12. Bridport Sands 130 



13. Down-Cliff Clay 70 



14. Junction-Bed : fine creamy-white lithographic 



stone in paper-like laminae {Grainmoceras of 

 Whitbian striatiihim-tJiouarsense types) and yellowish 

 conglomerate, somewhat sandy, with derived 

 Tetrarliynchia thorncomhiensis. For detailed 

 section, see later, p. 387 5 



Domerian 15. Thorncombe Sands ^: yellow sands with doggers 35 



16. Blueclay2 2 



17. Margaritatus Bed: a prominent and easily re- 



cognized datum-line 1 



18. Down-Cliff Sands.^ 



Approximate total 624 



The accompanying diagram (1) embodies a general sketch of 

 Watton cuff. 



^ Name given from their occurrence at Thorncombe Beacon. 



2 The equivalent of this at Down Cliffs was wrongly placed in my section 

 (I, 5, p. 66) copied from Day, and the thickness omitted. The / should be 

 just above g there, and the thickness (6| feet) should be put opposite ; see 

 *E. C. H. Day, III, p. 285. 



■^ From their occurrence at Down Cliffs ; see Day, as above. 



