Eozoic Age. 71 



The eozoa are the earliest forms of foraminiferous animals found 

 fossil. Dr. Dawson shows that the eozoa grew in large masses and in 

 various forms, in the upper part of the Lower Laurentian series of rocks. 

 And he calls attention to the fact that far below the strata in which the 

 eozoon is found, are vast beds of metamorphic limestone, in which the 

 traces of animal life are destroyed, but which, without doubt, were en^ 

 tirely made up of the calcareous shells of these simple animals. 



The Lower Laurentian rocks of Canada are about 35,000 feet in ag- 

 gregate thickness, of which three limestone beds amount to 3,500 in 

 thickness. There are also large quantities in some places amounting 

 to 20 to 30 feet in thickness of carbon in the form of graphite all of 

 which, without doubt, is the product of vegetation, and shows that for 

 untold ages before the beginning of the Silurian era the first era cred- 

 ited with organic life, by the early geologists simple forms of both an- 

 imal and vegetable life flourished in immense abundance. In fact the 

 world was an old world at the beginning of the Silurian age. 



The total thickness of the series of metamorphic or Eozoic rocks of 

 Canada, is not less than six miles, and in some places may reach nine. 

 The same system, in some parts of Europe, has a thickness of 90,000 

 feet or seventeen miles. 



Dr. Dawson's conclusions relating to the eozoon fossils, have been 

 disputed in some quarters, it being held that the present state of the 

 fossils is such that on account of the great heat they were subjected to in 

 metamorphic times, no certain conclusion as to their origin is war- 

 rantable. Well, granting that the fossil itself is not sufficiently well 

 preserved to be identified with certainty, there are those vast layers of 

 limestone and graphite to be accounted for. 



Dawson holds that there is no possible origin for the graphite except 

 through vegetation, that there is no agency except plants that will disen- 

 gage the oxygen from the carbonic acid. Dana holds the same view 

 practically. In regard to the formation of the limestone strata Dana 

 says there is only one way in which limestones can be formed in water, 

 and that is by the wear and accumulation of shells of animals. The 

 limestones of the Silurian and later ages have nearly all been made from 

 crinoids, corals and the calcareous relics of other animals. He cites 

 strata of the Silurian period, which are presumed to be composed of the 

 remains of microscopic cells of rhizopod animals. If the limestones of 

 the Silurian and later ages were made from shells, there is equal reason 

 for supposing them to have originated in the same way in the earlier ages. 



The rhizopod is of the same organic value as the eozoon of Dr. 

 Dawson, and is, in fact, nothing more than a microscopial bit of proto- 

 plasm surrounded with a minute shell of limestone perforated with holes, 

 through which the animal projects slender processes of his protoplasm, 



