Geological Society. 235 



It will be seen that the combination of conductors that has 

 been described is essentially the same as that constituting Wheat- 

 stone's " electrical balance ;" in fact the whole experiment con- 

 sists in purposely exaggerating an effect which, in comparing 

 electrical resistances by means of that arrangement, it is neces- 

 sary to get rid of by a well-known artifice in the mode of making 

 contact. 



XXVIII. Proceedings of Learned Societies. 



GEOLOGICAL SOCIETY. 

 [Continued from p. 164.] 



December 23rd, 1868.— Prof. T. H. Huxley, LL.D., F.R.S., 



President, in the Chair. 



THHE following communications were read : — 

 ■*■ 1. " On the so-called < Eozoonal ' Rock." By Prof. W. King and 

 Dr. T. H. Rowney. Communicated by Sir R. I. Murchison, Bart., 

 K.C.B., F.R.S., V.P.G.S. 



The authors noticed that, since the reading of their former commu- 

 nication in 1866, further descriptions of Eozoon have been published 

 by Hochstetter, Giimbel, Carpenter, Dawson, and Logan ; and after a 

 few words on those by the first two, they proceeded to criticise the 

 others more fully, intimating that the English and Canadian observers 

 have by no means mastered all the difficulties of the subject, nor 

 answered the objections brought forward by them. In the course of 

 these remarks, Messrs. King and Rowney, objecting to the specimen 

 from Tudor, of which they have seen the photograph, and which was 

 described and figured in 1867 (Q. J. G. S, No. 91), suggested that 

 it is nothing more than the result of infiltration of carbonate of 

 lime, with entangled impurities, between two layers of the sandy 

 limestone. They also stated their belief that the term " Eozoonal " 

 is applicable to any of the ophites they describe, inasmuch as, it was 

 contended, the structure of the latter is similar to that of the Cana- 

 dian rock containing the so-called Eozoon. 



The authors then proceeded to treat of the supposed foraminiferal 

 characters of " Eozoon." First, as to the " cell- wall " or " nummu- 

 line layer," they advanced repeated evidence of the value of their 

 former proofs that the typical form is due to aciculate serpentine 

 (or modified chrysotile) of inorganic origin, having examined, be- 

 sides others, a Canadian specimen presented by Dr. Carpenter. 

 Secondly, nothing new was adduced with regard to the mineral 

 structure of the so-called " intermediate skeleton." Thirdly, in proof 

 that the " chamber-casts " are not of organic origin, the authors 

 referred to their former work, and stated .that chondrodite and pyral- 

 lolite may be added to the list of minerals that occur, as such, disse- 

 minated in limestones. They thought it strange that a carbonate, as 

 well as a silicate, should not have been found filling the so-called 



R2 



