422 ME. s. s. EUCKMAX OX [vol. Ixxviii, 



It is now known that a similar lithographic stone was deposited 

 horizontally and normally at an earlier date at Watton Cliff, of 

 which the unfaulted part is preseiwed and the faulted part rendered 

 inaccessible : it is reasonable to conclude that the Burton White 

 Bed was deposited in a normal manner, but that the unfaulted 

 part has been destroj^ed and only the faulted part preserv^ed. A 

 somewhat complicated series of events which involves faulting and 

 penecontemporaneous erosion must be postulated, but nothing that 

 is not already known in other cases. 



Thus, in regard to the White Bed, there are the following 

 facts : — 



(i) That the White Bed is of later date than the Red Bed, and earlier than 

 the AstaHe Bed. 



(ii) That the White Bed is not now fonnd resting upon the Red Bed. 



(iii) That the White Bed is not found separating the Red Bed from the 

 Astarte Bed. 



(iv) That the White Bed is a finely- stratified laminated deposit — in part, at 

 any rate. 



(v) That the White Bed is let down in a fault some 50 to 60 feet below the 

 top of the Red Bed : that is, below its original position. 



(vi) That it is mixed up with Bridport Sands. 



(vii) That hard rocks of dates subsequent to that of the White Bed — that 

 is, strata of the hemerte Garantiana to zigzag — are not found associated with 

 broken-up masses of the Red Bed. 



Next, the following inferences may be drawn : — 



(i) That the White Bed was deposited discontinuously on a surface of the 

 Bridport Sands to the east, but with fair continuity on the surface of the Red 

 Bed to the Avest. 



(ii) That the White Bed is a deposit of slow accumula':ion, laid down under 

 conditions similar to those of the lithographic stone of the Watton Bed. 



(iii) That the White Bed deposited on the Bridport Sands must have been 

 protected from the denuding agency. 



(iy) That the preservation of the White Bed is apparently due to a small 

 syncline in the Bridport Sands. 



(v) That the White Bed was removed from the top of the Red Bed before 

 the commencement of the deposition of the Astarte Bed. 



(vi) That the hard rocks of the strata of hemerse Garantiana to zigzag 

 must have been either not deposited on the top of the White Bed of the 

 Bridport- Sands tract, or, if deposited, they must have been completely re- 

 moved again, otherwise they would be found associated with fallen blocks 

 of the White Bed. 



(vii) That non- deposition of these strata on the top of the White Bed 

 would mean the elevation of the sand tract above the water, and would there- 

 fore expose it to denudation, which would bring about the total loss of the 

 White Bed. 



(viii) That deposition of these strata on the White Bed is a necessary 

 supposition ; but that this requires a postulate as to their subsequent removal. 



(ix) That it is necessary to suppose that a soft rock easily yielding to 

 denudation — a rock like the clays of the Fuller's Earth— was the immediate 

 covering of the White Bed at the time when faulting occurred, as such a rock 

 could easily disappear from the face of the White Bed A\-ithout leaving any 

 traces. , 



i 



