IN THE ANGLO-PARIS BASIN 51 



675). In this, he was very nearly right, for the concretions at Black Head yield, 

 albeit very rarely, early forms of Anahoplites of the intermedins group. These 

 include the specimen figured by Spath as A. mimeticus (1927 ; 188, pi. XVII, fig. 8a, b) 

 which belongs to A. osmingtonensis sp. nov., and A. grimsdalei sp. nov. which is the 

 direct forerunner of A . evolutus a form found at the base of the intermedins Subzone. 

 These early Anahoplites are associated with the usual species of Hoplites (H.) of this 

 bed, however, it is important to note Cunnington's remark (1929 ; 126) : 'Ana- 

 hoplites — are scarcer, but wherever one is found there are almost always others or 

 fragments of others in the same block '. I have not yet found Anahoplites in this line 

 of concretions containing an upper spathi Subzone fauna. This might be purely a 

 collecting error, for the matrix and mode of preservation of the specimens of Ana- 

 hoplites is identical to that of the other fossils of this bed and this is very distinctive. 

 From a morphological point of view these are unquestionably earlier than the basal 

 intermedins Subzone species of this genus, e.g. A. evolutus (p. 151). Equally certain, 

 they are not earlier than the high spathi Subzone concretions ; that is, they are not of 

 lyelli Subzone age. The sections in this area are shown in Arkell (195 1 ; Fig. 4). 



Deposits of lautus Zone age are also present in this area (Cunnington 1929 ; 129 : 

 Spath 1943 ; 743 : Wright in Arkell 1947 ; 193) but the position in the section of the 

 material picked up loose has yet to be determined. 



(iii) THORNCOMBE BEACON TO BLACK VEN 



The account of the sections on Golden Cap, and Black Ven, given by Jukes-Browne 

 (1900 ; 182-189) was followed fourteen years later by the very important detailed 

 account by Lang (1914) who also discovered the formation on Stonebarrow. To this, 

 additional information was added in Lang & Thomas (1936), and these sections to- 

 gether with that on Thorncombe Beacon east of Seatown have more recently been 

 described by Welch (in Wilson, Welch, Robbie & Green 1958 ; 139-150). Here 

 again, there is nothing to add to the lithological account but a re-examination of the 

 ammonites has provided a little, but important, additional information. The 

 sediments classified with the Gault are much thinner in this area of the coast. 



Bed 1 of Lang (1914) yielded Anahoplites praecox both at Black Ven and Stone- 

 barrow (1936 ; 310). Bed 2 on Stonebarrow has also yielded A. praecox including 

 one specimen BMNH., C 15661 which is very close indeed to the neotype of ' Dimor- 

 phoplites ' alternatus, which is in reality a very coarse development of A . praecox 

 (p. 153). A. praecox also occurs at Chart on Goyle in a matrix which is almost cer- 

 tainly the unweathered representative of Bed 2 (BMNH., C 68394-6). Beds 1 and 2 

 definitely belong to the intermedins Subzone. According to Spath (e.g. 1943 ; 744), 

 Bed 3 contains both intermedins Subzone and varicosum Subzone ammonites. This 

 is untrue. BMNH., C 41035 from Bed 3, recorded by Spath as Epihoplites aff. 

 trifidus, is in reality an early transition between Hoplites (H.) and Dimorphopiites 

 consistent with an intermedins Subzone age. The ' Idiohamites of the turgidus 

 group ' (BMNH., C 41038) is a Protanisoceras (H.) cf. nodosum, also indicating an 

 intermedins Subzone age. Another specimen BMNH., C 41035 from Bed 3 is here 

 identified as Anahoplites cf. intermedins. 



