Ix PEOCEEDINGS OF THE GEOLOGICAL SOCIETY. 



Hence we may be certain that, contemporaneously with the 

 JEozoon, there mtist have existed other creatures, probably minute 

 Infusoria, floating in the waters of this Laurentian ocean, as well 

 as marine Plants and Algse, from which they derived their nourish- 

 ment, growing on the muddy bottom of the sea, which has since 

 been metamorphosed into gneiss. It is true no trace of them has 

 been found. This is probably owing to the metamorphic action 

 having operated more violently on marls and sands deposited 

 in the ocean, than on the intercalated bands of limestone or Eozoon- 

 reefs, and to the subsequent crystallization and rearrangement of 

 the constituent molecules having destroyed all traces of the mi- 

 nute Infusoria, or of the tissue of the Algse. 



At all events we may be sure that this important question will 

 not escape the notice of Sir W. Logan and his associates, and that 

 no endeavours will be neglected on their part to render their 

 search for fresh evidence of these fossil remains successful ; and 

 even should they fail in their endeavours to complete our know- 

 ledge of these early pages of the book of nature, we shall still 

 owe them our thanks for having thus deciphered these ancient 

 Avritings, and extended our knowledge of organic life so far beyond 

 its previously recognized limits. 



Since Avriting these remarks, my attention has been directed to 

 a notice by Mr. Sanford, in the last TsTumber of the Greological 

 Magazine (No. VIII. p. 87), of the discovery oi t\\e Eozoon Gana- 

 dense in the Green Marble of Counemara, in a quarry of the 

 Binabola Mountains. The correctness of this statement is con- 

 firmed by Prof. T. E. Jones, Avho, on submitting thin slices to the 

 microscope, discovered all the essential features described by 

 Dr. DaAVSon and Dr. Carpenter. This formation, therefore, must 

 be considered as Laurentian ; and it is a strong confirmation of 

 this view, that Mr. Sanford describes these green marbles as 

 having a IST.W. and S.E. strike, precisely like the fundamental 

 or Laurentian gneiss of the JN". W. of Scotland already mentioned. 



In connexion with this subject I may also refer to Sir E. Mur- 

 chison's description of these Counemara moimtains (Siluria, third 

 edition, p. 190), where he mentions the green marble or serpen- 

 tine as interstratified with the lower portion of the series of 

 altered or metamorphic micaceous and quartzose schists which, 

 resting on granite and syenitic and hornblendic rocks, underlie 

 the fossiliferous Silurian beds. 



Amongst the recently published reports of the Geological 

 Survey of Canada is a memoir on the Graptolites of the Quebec 

 Group, by Professor James Hall, accompanied by twenty-two plates 

 re])resenting the singular and diversified forms in which this 

 remarkable family of Palaeozoic polypiform Eadiata occur. In the 

 first chapter Avill be found a carefully digested description of the 

 structure and mode of growth of these animals, in some cases 

 closely resembling that of the Sertularise of the present day, and 

 of the different classes into which they have been subdivided. 

 This, however, notwithstanding many attempts, the author thinks 



