170 W. A. Bell — Mississippian Formations of 



A. Vaughan, have worked out in great detail the faunal 

 sequence in their Lower Carboniferous or Avonian rocks 

 (Vaughan 1905, 1915; Garwood 1912; DLxon 1911). 

 While opinions differ as to the placement of the division 

 line between the Tournaisien and Viseen, there is general 

 agreement as to the faunal successions throughout the 

 British and Belgian field. The northern part of the 

 British Isles, however, is characterized by an arenaceous 

 or abnormally marine facies and much remains yet to be 

 done on the correlation of the beds that make up the Cal- 

 ciferous and Limestone series of Scotland. The latter 

 facies is rich in the Mollusca as contrasted to the coral- 

 brachiopod faunas of the calcareous or ^^ Mountain lime- 

 stone'' facies. 



In comparing the "Windsor faunas with the Avonian 

 faunas of England, the affinities are seen to lie with the 

 upper Avonian or Viseen rather than with the lower 

 Avonian or Tournaisien. The presence in the lower 

 Windsor zone of abundant Composita of the " ficoides'^ 

 form, associated with Productus of the type of cora and 

 corrugato-liemispliericus, is in striking conformity with 

 the faunal assemblage in the middle Viseen (S2) of the 

 Avonian sequence. Of the Mollusca, which dominate the 

 lowest fauna at Windsor, there are species identical with 

 or closely allied to species from the Lower Limestone 

 series of Scotland, or from the Redesdale limestone of 

 Northumberland, both of which are well up in the Viseen. 

 Thus, Sanguinolites parvus n. sp. is probably synonymous 

 with 8. striatogranulatus Hinde from the Eedesdale; 

 specimens of S. trico status identical with Portlock's spe- 

 cies from the Redesdale limestone occur at Windsor ; Lith- 

 odomtis lingualiformis n. sp. is very close to L. lingualis 

 Phillips from the Viseen of Castleton ; Murchisonia com- 

 pacta is identical with M. compacta Donald from the 

 Upper Limestone series of Dairy, Scotland. 



The upper or Martinia zone at Windsor is character- 

 ized by the entrance of a clisiophyllid cup coral belonging 

 to the genus Bihunopliyllum, which is an early form of 

 the type of Dihunopliyllum aff. »A Vaughan, as well as by 

 the abundant occurrence of Martinia of the M. glabra 

 form type. Both of these genera are characteristic 

 Viseen genera, and Bihunopliyllum especially has been 

 found a good index to the upper Viseen of England.^ The 

 following species from the upper limestone of Windsor 

 afford additional links on which a correlation of the 



