258 A. J. Jukes-Browne — Purheck Beds, Vale of Wardour. 



chapter on the Lower Green sand, and then remarks that he doubts 

 our correlation of the clays at Dinton and Teffont. 



Here, again, therefore, it is a matter of opinion, and those 

 responsible for the published mapping of this bit of ground do not 

 see in able to give very good reasons for their beliefs. We suppose 

 Mr. Eeid correlates the yellow silty clay of Teffont with the yellow 

 grey and white clays at the top of the Dinton cutting, but in the 

 latter place there is nothing like the peculiar ' cat's-brain ' clay, and 

 until some one can find that kind of clay in the Upper Purbeck of 

 the Vale of Wardour I shall continue to regard it as belonging to 

 the Wealden, and to believe that Mr. Eeid has not carried the 

 Wealden far enough to the westward along the northern side of 

 the Vale. 



When describing the Purbeck Beds in 1894 we incidentally re- 

 marked that there was a complete discordance between the Purbeck 

 Beds and the Lower Cretaceous Series, " including the Wealden." 

 This was carelessly expressed : the great unconformity is undoubtedly 

 at the base of the Lower Greensand, but we certainly did think that 

 the Wealden overlapped the Upper Purbeck. Whether it really 

 does so depends on the correct separation of the Wealden from the 

 Purbeck. The bare idea of a break at the base of the Wealden 

 fluttered the dovecotes of Jermyn Street to such an extent that the 

 question seems to have assumed proportions of paramount importance 

 in the minds of Messrs. Woodward and Eeid. Others, however, 

 may deem it of equal importance that the divisions of the Purbeck 

 Series should be established on logical grounds, that the thickness 

 of each group should be carefully estimated, and that the outcrop of 

 the Wealden Beds should be carefully discriminated from that of the 

 Upper Purbecks. 



Finally, Mr. Eeid's reference to Endogenites erosa adds nothing to 

 the strength of his position. He admits that " it is too doubtful 

 a form to be of much value for correlation," but immediately adds, 

 " though its presence supports the view that the strata containing it 

 truly belong to the Wealden period, and are not, as supposed by 

 Messrs. Jukes-Browne and Andrews, of Purbeck age." He quite 

 ignores the fact that we found a large piece of similar endogenous 

 wood in the Upper Purbeck sand of the Dinton cutting. It is also 

 a fact that pieces of Endogenites erosa have been found close to the 

 spots where outliers of the Upper Purbeck are shown on the map, 

 and when it is remembered that the fossil wood has never been 

 found in the beds referred by Messrs. Woodward and Eeid to the 

 Wealden, it will be apparent that the facts are much more in accord 

 with our view than with Mr. Eeid's. 



In conclusion, I may place on record that I have submitted one 

 of the surface fragments to Mr. A. C. Seward, and he kindly informs 

 me that he believes it to be the true Endogenites erosa, now known 

 as TempsTcya Schimperi, and in reality the stem of a tree-fern. Un- 

 fortunately, I could not send him a piece of the wood found in the 

 sand at Dinton, and cannot therefore affirm that it was also TempsTcya, 

 but it was so similar that I took it to be the same. 



