1870.] DAWSON — LAURENTIAN GRAPHITE. 13 



The partial eclipse of the moon on the 27th January could not 

 be well observed, owing to clouds and hazy weather. 



The solar eclipse of the 7th August, which was only partial 

 at Montreal, was visible, and furnished some interesting phe- 

 nomena. 



ON THE GRAPHITE OF THE LAURENTIAN OF 



CANADA. 



By J. W. Dawson, LL.D., F.R.S., F.G.S. 



(From the Quarterly Journal of the Geological Society for Feb., 1870.) 



In my paper of 1864, on the Organic Remains of the Lauren- 

 tian Limestones of Canada, as a sequel to the description of 

 Eozoon Canadense, I noticed, among other indications of organic 

 matters in these limestones, the presence of films and fibres of 

 graphitic matter, and insisted on tl# probability that at least 

 some of the lower forms of plant life must have existed in the 

 seas in which gigantic Foramiuifera could flourish. Dr. Hunt 

 had previously, on chemical evidence, inferred the existence of 

 Laurentian vegetation^, and Dana had argued as to the proba- 



* " American Journal of Science" (2), xxxi. p. 395. From this article 

 written iu 1861, after the announcement of the existence of laminated 

 forms supposed to be organic in the Laurentian, by Sir "W". E. Logan» 

 but before their structure and affinities had been ascertained, I quote 

 the following sentences : — " We see in the Laurentian series beds and 

 veins of metallic sulphurets, precisely as in more recent formations ; 

 and the extensive beds of iron-ore, hundreds of feet thick, which 

 abound in that ancient system, correspond not only to great volumes 

 of strata deprived of that metal, but, as we may suppose, to organic 

 matters which, but for the then great diffusion of iron-oxyd in conditions 

 favourable for their oxydation, might have formed deposits of mineral 

 carbon far more extensive than those beds of plumbago which wa 

 actually meet in the Laurentian strata. All these conditions lead us then 

 to conclude the existence of an abundant vegetation during the Lauren- 

 tian period." 



Since the above note was printed in the Quarterly Journal, I have 

 ascertained that it is innacurate as to dates : Dr. Hunt having, in May 

 1858, before the discovery of Eozoon Canadense, asserted, in an article 

 in the Amer. Journal of Science (xxv. 436), that " the presence of iron 

 ores, not less than that of graphite, points to the existence of organic 

 life even during the Laurentian or so-called Azoic period." The same 

 argument will be found in more detailed form, in his papers Quar. Jom*. 



