BY T. W. EDGEWORTII DAVID AND WALTER HOWCIIIN. 573 



that some of the leadini^ authorities on the radiolaria are not 

 convinced as to the structure of the forms figured by M. L. 

 Cayeux being correctly referred to the abo\e group, and his 

 further descriptions of the Brittany rocks are anxiously awaited. 

 Reference may be made here to what have been described as other 

 niicro-oriiianisms associated with the Pre-Cambrian radiolaria, or 

 occurring alone. 



M. L. Cayeux has described and figured what he believes to be 

 foraminifera from Pre-Camljrian rocks at Saint Lo, at Lamballe 

 (Cotes-du-Nord).-'- 



He has also recorded the occurrence of remains of sponge 

 spicules in the Pre-Cambrian rocks of Brittany, f 



These were found by M. Ch. Barrois, who also discovered the 

 radiolaria in the Pre-Cambrian rocks of Brittany, from Ville-au- 

 Roi, near Lamballe. These remains are in the form of monaxial 

 spicules, some being probably referable to the Monactinellidie. 

 Others M. L. Cayeux refers respectively to the Tetractinellid ce, 

 Lithistidce, and Bexacthiellidce. The spicules are from "05 mm. to 

 ■35 mm. in length, mostly -1 mm. to "15 mm. The spicules are 

 replaced by pyrites : the particles of pyrites are held together in 

 a siliceous setting. The canal is not preserved. 



The occurrence of spicules of fossil sponges in Archaean rocks 

 has been recorded by Mr. G. F. Matthew. | 



These are referred to Cyathos^yo^igia (?) Uozoica, and to Haliclton- 

 drites graphitiferus. They are stated to occur in Upper Lauren- 

 tian rocks. 



The authenticity of these remains has been called in question 

 by Mr. Herman Rauff.§ 



*C. R. Ac; Sc. Janvier-Juin 1894, pp. 1433-1435. 



t Societe G(5ologique du Nord. Annales xxiii. 1895, pp. 52-64. pis. i.-ii. 

 L. Cayeux. — De Texistence de iiombreux debris de Spoiigiaires dans les 

 phthauites du Pre-Canibrien de Bretagiie. C.E. Ac. Sc. T cxx.pp. 279-282. 



X On the Occurrence of Sponges in Laurentian rocks at St. John, jST.B. 

 Bull. Nat. Hist. Soc. New Brunswick, No 9, pp. 42-45. 



§ H. Banff. UelxiV cuujthlkhe Spoiujien ana dem Archaiciim, Neues Jahr. 

 ftir ilin., Geol. und Pal. II. Bd. 1893, pp. 57-67, and Pakeosponyiologie, 

 Palffiontographica, 1893, Bd. 40, p. 233. 



