398 ME. s. s. buckmajS' on [vol. Ixxviii, 



massive sandstone-beds of the Down-Cliff Sands at the latest, but 

 may come from the Starfish-Bed or the Shell-Bed. No sign of the 

 rest of the fauna which was found in the Scalpa Sandstone in the 

 same matrix as that of AmaltJwus IcBvis was seen at Thorncombe. 

 If A. IcBvis comes from the Starfish-Bed and Seguenziceras 

 from the immediatel}'^ subjacent Shell-Bed, while there seems to 

 be some 200 feet between A. Icdvis and ^eguenziceras at Raasay 

 in the Scalpa Sandstone,^ a very interesting position would be 

 reached, but one quite analogous to what is found in other cases. 

 Some 200 feet would have to be added where now is little or no 

 deposit. The already thick strata of the Domerian on the Dorset 

 coast would still lack representatives of a time-interval equal to 

 some 200 feet of deposit. The length of time required for the 

 deposition of the Domerian is thus likely to increase to a large 

 figure : it is already considerable. 



These points cannot be pursued now, but they show where 

 further work is required. It is obvious that the complication of 

 the Domerian succession will be much greater than has been 

 expected, and that the dating of the Scalpa Sandstone may have 

 to be considerably modified. But that will not be at all a simple 

 matter : it will immediately raise many other questions, among 

 them perhaps that of local denudation of the Scalpa Sandstone — 

 and that presents difficulties. 



The Domerian succession disclosed by Thorncombe may be stated 

 as follows : — 



(7) Paltopleriroceras spinatu')n. 



(6) ' Tetrarhynchia tliorncomhiensis.' 



(5) Lytoceratid (the margaritatus bed). 



(4) Cuboidal Rhynchonellids. 



(3) Starfish-Bed (^? Amaltheus Isevis). 



(2) Seg^ienziceras. 



(1) Amaltheus clevelaoidicus. 



This sequence is, in all probability, incomplete for the Domerian 

 strata of Thorncombe Beacon — because, for one thing, it has not 

 yet been possible to extract from their matrix all the specimens 

 collected, — and it is certainly incomplete so far as the full 

 Domerian sequence is concerned. Faunal elements of the 

 Hebrides and Yorkshire are missing, and will have to be accounted 

 for ; but, more important still, faunal elements of the Ilminster 

 district and of Normandy — that is, faunal elements immediately^ 

 north and south of Dorset — are lacking. 



Some interesting examjDles of this are the following : — Aiila- 

 cotlip^is resvpinata and A. moorei occur at Ilminster and in 

 Normandy. The absence from the Dorset-coast sections of Tere- 

 hratula \Aulacotliyris\ resupinata (including T. \_A.~\ moorei 

 presumably) is particularly noted by Day." Walker mentions 

 this, and says nothing to the contrary. ^ M}^ experience is the 



1 I, 7, p. 261. - III, p. 293. ^ XII, p. 442. 



