42 



Girvanclla also finds an extensive distribution in the lower Car- 

 boniferous of Britain ; E. Wethered^^ described G. incriistaus, with tubes 

 having a diameter of o.oi mm. and G. diicii, with a diameter of 0.02 mm. from 

 the limestone of this age of the Avon gorge and Tortworth, England. Gar- 

 wood^' remarked that these organisms must have flourished at this period 

 over an area of at least 3,000 sq. miles in the north of England alone. The 

 Girvanelln nodular bed occurs at the base of Vaughan's xw^ii^ax Dihunophylliuii 

 zone. 



According to Deprat,*^ the Moscovian limestone of Tha-tchong in Yun- 

 nan contains Girvanclla sp. 



The youngest geological horizon in which the occurrence of Girvanclla 

 has been confirmed is the British Oolites; according to Wethered,^' Girvanclla 

 tubes are fairly abundant in the Leckhampton pisolites {G. pisolitica), and 

 coralline oolite of Weymouth {G. iiiinuta and G. intermedia). 



Locality : — San-yu-tung, Tung-hu-hsien, and Liu-chia-ho, Hsing-shan- 

 hsien, both in the province of Hu-pei. 



Tetracoralla. 



Zaphrentidse. 



Polyrophe, Lindstrom. 

 Polyrophe (?) dabia Vabe, sp. nov. 

 PI. XV., Fig. 5a.-d. 



Coralluui simple, short horn shaped ; circular in cross section ; surface 



1) A. F. Foerste: Upper Ordovician Formations in Ontario and Quebec. Mem. Geol. Surv. 

 Canada, LXXXIII., p 178. 1916. 



2) Garwood: I.e. p, 498. 



3) Wethered: The Inferior Oolite of the Cotteswold Hills with special Reference to its 

 Microscopic Structure. Q. J. Geoi.. Soc. London, vol. XLVII. 1891. p. 550 et seq., 

 pi. XX. We'i'hered: On the Microscopic Structure of the Jurassic Pisolite.. Geol. 

 Mag. Dec. III., vol. VI., p. 200. 



4) Deprat: Etude Geol. du Yun-nan oriental; Geologie generals, p. 107. 



