48 PROCEEDIXGS OF THE GEOLOGICAL SOCIETr. [NoY. 23, 



the Laurentian series, seemed to be an evidence of the existence of 

 vegetation, since no one disputes the organic character of this 

 mineral in more recent rocks. Mj colleague, Dr. T. Sterry Hunt, 

 has argued for the existence of organic matters at the earth's 

 surface during the Laiirentian period from the presence of great 

 beds of iron-ore, and from the occurrence of metallic sulphurets ; 

 and, finally, the evidence was strengthened by the discovery of 

 supposed organic forms. These were first brought to me, in 

 October 1858, by Mr. J. McCulloch, then attached, as an explorer, 

 to the Geological Survey of the province, from one of the limestones 

 of the Laurentian series, occurring at the Grand Calumet, on the 

 Eiver Ottawa. 



Any organic remains Avhich may have been entombed in these 

 limestones would, if they retained their calcareous character, be 

 almost certainly obliterated by crystallization ; and it would only be 

 by the replacement of the original carbonate of lime by a different 

 mineral substance, or by an infiltration of such a substance into all 

 the pores and spaces in and about the fossil, that its form would be 

 preserved. The specimens from the Grand Calumet present parallel 

 or apparently concentric layers, resembling those of Stromatopora, 

 except that they anastomose at various points. What were at first 

 considered the layers are composed of crystallized pyroxene, while the 

 then supposed interstices consist of carbonate of hme. These 

 specimens, one of which is figured in the ' Geology of Canada,' 

 page 49, called to memory others which had, some years previously, 

 been obtained from Dr. James Wilson, of Perth, and were then 

 regarded merely as minerals. They came, I believe, from masses in 

 Burgess, but whether in place is not quite certain ; and they exhibit 

 similar forms to those of the Grand Calumet, composed of layers of 

 dark-green sihcate of magnesia (loganite), while what was taken 

 for the interstices are filled with crystallized dolomite. If the 

 specimens from both these places were to be regarded as the result 

 of unaided mineral arrangement, it appeared to me strange that 

 identical forms should be derived from minerals of such different 

 composition. I was therefore disposed to look upon them as fossils, 

 and as such they were exhibited by me at the meeting of the Ame- 

 rican Association for the Advancement of Science, at Springfield, in 

 August 1859. In 1862 they were sho"«Ti to some of my geological 

 friends on this side of the Atlantic ; but no microscopic structure 

 having been observed belonging to them, few seemed disposed to 

 believe in their organic character, with the exception of my friend 

 Professor Ramsay. 



One of the specimens had been sliced and submitted to microscopic 

 examination, but unfortunately it was one of those composed of 

 loganite and dolomite. In these, minute structure rarely occurs. 

 The true character of the specimens thus remained in suspense until 

 last winter, when I accidentally observed indications of similar 

 forms in blocks of Laui^entian limestone which had been brought to 

 our museum by Mr. James Lowe, one of our explorers, to be sawn 

 up for marble. In this case the forms were composed of serpentine 



