326 Geological Society of London. 



If this inference be correct, tlie author suggests that it may lead to 

 the determination of the nature of the medium in which these minute 

 fishes, of the size of Minnows or Sticklebacks, lived, apparently 

 associated with Batrachia, and now entombed in beds composed of 

 the carbonized remains of land-plants and semi-aquatic vegetation. 



With regard to the genera and species here indicated, Professor 

 Owen does not object to the possibility that one or more forms of 

 teeth may have belonged to different parts of the same mouth (e.g. 

 Mitrodus and Dittodus) ; the author considers, however, that it will 

 afford most facility to future investigators of these Coal-remains, 

 if they are able definitely to express the nature of the fragment they 

 may have discovered by referring it to one or other of the forms here 

 described. 



Professor Owen, in his paper, treats at considerable length of 

 the form and histology of each genus and species recorded, and a 

 series of fifteen elaborately-prepared plates have been drawn by 

 Mr. Tuffen West for its illustration. The whole paper forms one of 

 the unpublished Chapters for a Second Edition of Professor Owen's 

 " Odontography." 



Geological Society of London. — ^I. May 8, 1867. — Warington 

 W. Smyth, Esq., M.A., F.K.S., President, in the chair. The 

 following communications were read: — 1. "On new specimens of 

 Eozoon." By Sir W. E. Logan, LL.D., etc. 



Amongst several additional specimens of Eozoon which have been 

 obtained during recent explorations of the Canadian Geological 

 Survey, is one which was found last summer by Mr. G. H. Vennor, 

 in the township of Tudor, county of Hastings, Canada West. It 

 occurred on the surface of a layer, three inches in thickness, of dark- 

 grey micaceous limestone, or calc-schist, near the middle of a gTeat 

 zone of similar rock. This Tudor limestone is comparatively un- 

 altered, and, in the specimen obtained from it, the skeleton of the 

 fossil, consisting of white carbonate of lime, is imbedded in the 

 limestone without the presence of serpentine or other silicate, a fact 

 which the author regarded as extremely favourable to the view of 

 the organic origin of Eozoon. Sir William Logan also described the 

 nature and relations of the rocks of other localities which have 

 recently yielded Eozoon, especially Wentworth, Long Lake, and 

 Cote St. Pierre. 



2. "Notes on Fossils recently obtained from the Laurentian rocks 

 of Canada, and on objections to the organic nature of Eozoon." By 

 J. W. Dawson, LL.D., F.E.S., F.G.S. 



The first specimen described in this paper was the one from Tudor 

 referred to in the previous communication. Its examination had 

 enabled Dr. Dawson to state, that in it the chambers are more con- 

 tinuous, and wider in proportion to the thickness of the septa, than 

 in the specimens found elsewhere, and that the canal-system is more 

 delicate and indistinct. Without additional specimens the author 

 could not decide whether these differences are of specific value, or 

 depend on age, variability, or state of preservation ; he therefore 



