112 
PROCEEDINGS 
OF 
THE GEOLOGICAL SOCIETY, 
POSTPONED PAPERS. 
1. On the Grapuite of the LAURENTIAN of CaNnaDA. 
By J. W. Dawson, LL.D., F.R.S., F.G.S. 
(Read June 23, 1869 *.) 
In my paper of 1864, on the Organic Remains of the Laurentian 
Limestones of Canada, as a sequel to the description of Hozoon 
Canadense, I noticed, among other indications of organic matters in 
these limestones, the presence of films and fibres of graphitic matter, 
and insisted on the probability that at least some of the lower forms 
of plant life must have existed in the seas in which gigantic Fora- 
minifera could flourish. Dr. Hunt had previously, on chemical 
evidence, inferred the existence of Laurentian vegetationt, and 
Dana had argued as to the probability of this on various grounds? ; 
and my object in referring to these indications in 1864, as well as 
to the supposed burrows of annelids, subsequently described by me§, 
was to show that the occurrence of Hozoon was not to be regarded 
as altogether isolated and unsupported by probabilities of the ex- 
istence of organic remains in the Laurentian deducible from other 
considerations. 
Now that the questions which have been raised regarding Hozoon 
* For the Discussion on this paper see p. 406 of the last volume of the 
Journal. 
+ ‘American Journal of Science’ (2), xxxi. p. 395. From this article, written 
in 1861, after the announcement of the existence of laminated forms supposed 
to be organic in the Laurentian, by Sir W. EH. 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 we actually meet in the 
Laurentian strata. All these conditions lead us then to conclude the exist- 
ence of an abundant vegetation during the Laurentian period.” 
{ Manual of Geology. I may also be permitted to refer to my own work 
‘Archaia,’ p. 168, and Appendix D, 1860. 
§ Quart. Journ. Geol. Soc. vol. xxii. p. 608. 
