12 



SHELVE DISTRICT 



80 



60 



CO 



V 50 



o 



<D 

 Q. 



o~> 



40 



30 

 

 E 20 



c 

 lOH 



ABCDE FGH 



formations 



Fig. i . Graph showing the estimated number of species recorded per 300 m of : Mytton 

 Flags (A) ; Hope Shales, Stapeley Shales and Weston Beds (B) ; Betton Beds (C) ; 

 Meadowtown Beds (D) ; Rorrington Beds (E) ; Spy Wood Grit (F) ; Aldress Shales (G) ; 

 Hagley Shales (H) ; and Whittery Shales (I). 



proved useful so far. In its type area of Anglesey, this species occurs in Arenigian 

 rocks (Bates 1968 : 147) and is associated with Hesperonomiella which is probably 

 closely related to the Hesperonomia of the Shelve area. L. proava also occurs in 

 the contemporaneous Henllan Ashes of the Arenig district and authenticated reports 

 of its widespread occurrence are in sharp contrast to the lack of information on the 

 distribution of the other common Shelve brachiopod, Monobolina piumbea, or of 

 inarticulates generally in the Welsh successions. Clearly these early Ordovician 

 assemblages are in urgent need of investigation. 



Despite taxonomic neglect of the older Llanvirn brachiopod faunas, a fairly close 

 likeness between the Llanvirn -Llandeilo assemblages of W. Shropshire and Car- 

 marthenshire can be discerned. This is especially true when one takes into account 

 the longer ranging constituents of the fauna like Lingulella, Palaeoglossa, Paterula, 

 Pseudolingula and Schizomania which occur in both areas. However these species, 

 although indicative of similar biofacies, are not very useful for correlation which is 

 dependent on comparatively few articulate species. 



Tissintia prototypa is confined to the Weston and Betton formations of the Shelve 

 area, both of which should now be assigned to the Upper Llanvirnian Didymograptus 

 murchisoni zone according to I. Strachan (in Whittard 1966 : 297). The species is 



