﻿68 Canadian Record of Science. 



stated by Dr. Bonney would at once disappear. Speci- 

 mens of Eozoon or other fossils might be infiltrated or 

 filled with these silicates, and when the latter were super- 

 abundant they might form separate concretions or grains, 

 which might in some cases envelop the fossils or be 

 attached to them in irregular forms, just as one finds in 

 the case of the flints in chalk or the chert in some other 

 limestones.^ 



It is scarcely necessary to say that no objection to the 

 organic origin of the Eozoon can be founded on the fact 

 that many of the specimens are fractured, crushed, bent, 

 or faulted, by the movement of the containing rock, or on 

 the circumstance that well-preserved specimens should 

 be rare, and found chiefly in beds containing silicates 

 capable of injecting their cavities. On the other hand, 

 the circumstance that fracrments of Eozoon are abundant 

 in the limestone is one of the best possible proofs that 

 we are dealing with a calcareous organism. It would be 

 interesting to describe and figure a number of specimens 

 in our collections illustrating these points ; but to do so 

 would require an extensive illustrated memoir, for which 

 neither space nor means are at present available. 



I observe, in conclusion of this part of the subject, that 

 in any highly crystalline limestone we can hope to find 

 well-preserved fossils only when their cavities and pores 

 have been filled with some enduring siliceous mineral ; but, 

 on the other hand, that porous fossils, once so infiltrated, 

 become imperishable. It still remains to consider shortly 

 new facts bearing on the structure of Eozoon and its 

 possible biological affinities. 



8 It is a curious coiucideiice that Dr. Johnstoii-Lavis has described in the July 

 number of this Journal, the aqueous deposition at ordinary temperature of crystals 

 of pyroxene and hornblende, in cavities and crevices of bones included in an ash-bed 

 of recent date, and in presence of calcite. ajiatite, and fluoride of calcium, as in the 

 Grenville Series. This is a modern instance analogous to that suggested above. 



