96 THE CANADIAN NATURALIST. [April 



Hunt, has argued for the existence of organic matters at the 

 earth's surface during the Laurentian 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. McMullen, 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 River Ottawa. 



Any organic remains which 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 sub- 

 stance into all the pores and spaces in and about the fossil, that its 

 form would be preserved. The specimens from the Grand Calu- 

 met present parallel or apparently concentric layers resembling those 

 of Stromatopora, except that they anastomose at various points. 

 What were first considered the layers are composed of crystallized 

 pyroxene, when the then supposed interstices consist of carbonate 

 of lime. These specimens, one of which is figured, in ' Geology 

 of Canada,' p. 49,f 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 be- 

 lieve, from masses in Burgess, but whether in plaec is not 

 quite certain ; and they exhibit similar forms to those of the 

 Grand Calumet, composed of layers of a dark green magnesian sili- 

 cate (loganite) ; while what were taken for the interstices are filled 

 with crystalline 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 dis- 

 posed to look upon them as fossils, and as such they were exhib- 

 ited by me at the meeting of the American Association for the 

 Advancement of Science, at Springfield, in August 1859. See 

 Canadian Naturalist, 1859, iv, 300. In 1862 they were shown to 

 to some of my geological friends in Great Britain ; but no micros- 

 copic structure having been observed belonging to them, few seemed 

 disposed to believe in their organic character, with the exception 

 of my friend Professor Ramsay. 



* Quarterly Journal of the Geological Society, xv, 493. 

 [f Reproduced below, page 100, figures 1 and 2.] 



