10 THE DAWN OF LIFE 



fragments and imperfectly preserved specimens abound in 

 other parts of the bed. It is a great mistake to suppose that it 

 constitutes whole beds of rock in an uninterrupted mass. Its 

 true mode of occurrence is best seen on the weathered sur- 

 faces of the rock, where the serpentinous specimens project in 

 irregular patches of various sizes, sometimes twisted by the 

 contortion of the beds, but often too small to suffer in this way. 

 On such surfaces the projecting patches of the fossil exhibit 

 laminae of serpentine so precisely like the Stromatoporce of the 

 Silurian rocks, that any collector would pounce upon them at 

 once as fossils. In some places these small weathered speci- 

 mens can be easily chipped off from the crumbling surface of 

 the limestone ; and it is perhaps to be regretted that they have 

 not been more extensively shown to palaeontologists, with the 

 cut slices which to many of them are so problematical. One 

 of the original specimens, brought from the Calumet, and now 

 in the Museum of the Geological Survey of Canada, was of 

 this kind, and much finer specimens from Cote St. Pierre are 

 now in that collection and in my own. A very fine example is 

 represented on the plate facing this chapter, which is taken 

 from an original photograph. In some of the layers are found 

 other and more minute vesicular forms, which may be organic, 

 and these, together with 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 some- 

 times partially mineralised with pyroxene, dolomite, or common 

 limestone. The section in Fig. 4 will serve to show the atti- 

 tude of the limestone at this place, while the more general 



