24 



THE. DAWN OF LIFE. 



and tbese^ together with its fragmental remains, as 

 ingredients in the limestone, will be discussed in the 

 sequel. We may merely notice here that the most 

 abundant layer of Eozoon at this place, occurs near 

 the base of the great limestone band, and that the 

 upper layers in so far as seen are less rich in it. 

 Further, there is no necessary connection between 

 Eozoon and the occurrence of serpentine, for there are 

 many layers full of bands and lenticular masses of 

 that mineral without any Eozoon except occasional 

 fragments, while the fossil is sometimes partially 

 mineralized with pyroxene, dolomite, or common lime- 

 stone. The section in fig. 5 will serve to show the 

 attitude of the limestone at this place, while the more 

 general section, fig. 3, taken from Sir William Logan, 

 shows its relation to the other Laurentian rocks, and 

 the sketch in fig. 6 shows its appearance as a feature 

 on the surface of the country. 



NOTES TO CHAPTER II. 



(A.) Sir William E. Logan on the Laueentian System. 



[Journal of Geological Society of London, February, 1865. ] 



After stating the division of the Laurentian series into the 

 two great groups of the Upper and Lower Laurentian, Sir 

 WilHara goes on to say ; — 



" The united thickness of these two groups in Canada can- 

 not be less than 30,000 feet, and probably much exceeds it. 

 The Laurentian of the west of Scotland, acording to Sir Eode- 

 rick Murchison, also attains a great thickness. In that region 

 the Upper Laurentian or Labrador series, has not yet been 



