﻿Vo]. 66.~] JURASSIC STEATA OF SOUTH DORSET. 69 



Some 6| feet below the top of the sclssum bed are found sand- 

 burrs and sand-rock, yielding Ammonites of the aalensis pattern ; 

 they are good but not very easy to extract, and the sandy matrix 

 is removable with difficulty. 



Scattered blocks yielding Ammonites of the aalensis pattern 

 may be presumed to belong to this horizon : they have yielded 

 Oanavarina, Walker ia, Cotteswoldia, and various examples of 

 Alocolytoceras ivrighti : one, which broke up while a workman was 

 extracting it, was 20 inches in diameter ; there is also a Nautilus 

 near to N. multiseptatus, Foord & Crick. 1 



It may be presumed that it was from this horizon that 

 Canavarina digna (Monogr. p. cxlii) and WalJceria burtonensis 

 {p. cxxxix) were obtained, while possibly W. delicata (p. cxl) 

 and Canavarina steinmanni (p. cxlii) were just a few inches 

 higher, by analogy with Chideock. 



In a little knoll north of Freshwater, the name for the place 

 where the River Bredy enters the sea, west of Burton, there is a 

 section in sands — a few feet. It gave evidence for aalensis beds at 

 the top, and for moorei beds some few feet lower down ; but the 

 condition of the Ammonites allowed merely of a general determina- 

 tion of their facies. 



The Catulloceras dumortieri 2 was from a fallen block : it can only 

 be said that it belongs to a group indicative of an earlier date than 

 moorei hemera. The lower part of the sands in the cliff, where 

 they are accessible, seems to be particularly barren : so far as 

 Ammonites are concerned, nothing can be recorded; there are 

 Belemnites. 



The thickness of Bridport Sands shown in the Burton cliffs 

 would somewhat exceed 100 feet, and at intervals of every few feet 

 there are lines of sandburrs, or sometimes more continuous sand- 

 rock (see fig. 4, p. 70). As the sands (or sand-rock) become blue 

 -in the lower layers, which are exposed occasionally after exceptional 

 tides, it may be presumed that these sands rest upon a blue clay like 

 that at Down Cliffs. 



The White Bed or Nautilus Bed. — In the foregoing account 

 of t lie strata of Burton the bed which is of special interest, because 

 it is a new discovery, has not been mentioned, for the reason that 

 it is not found in the main cliff, nor in any of the quarries. It 

 only occurs in a more or less tumbled condition in the bank at the 

 beach opposite the villas, where the roadway comes to the shore 

 {see fig. 4, p. 70). It is particularly exposed on the sort of pathway 

 leading from the road to the beach, and just to the right hand as 

 one reaches the beach. 



The place where this bed is exposed is in the line of fault, a 

 downthrow to the east of 200 feet or more, which has brought 

 Bradford Clay and Forest Marble (Bathonian) of the East Cliff' of 



The specimen is now in tbe Museum of Practical Geology, Jermyn Street. 

 • Monogr. Inf. Ool. Amm.' p. 277 & pi. xxxix, figs. 6-9. 



