538 



THE AZOIC SYSTEM AND ITS SUBDIVISIOISS. 



which all this is revealed is as follows : " The Primeval Cell, together 

 with the Proof that Granite, Gneiss, Serpentine, Talc, certain Sand- 

 stones, also Basalt, and finally Meteoric Stones and Meteoric Iron, con- 

 sist of Plants/' This is only the carrying a little farther of the same 

 style of observation as that to which we are indebted for the Eozoon, 

 and that some one should follow this lino of research to the highest 

 pitch of absurdity seemed to be the one thing wanting to give the 



Eozoon the coup de grace. 



As already mentioned, it is held by Dana, as well as by many other 

 geologists, that the occurrence of limestone in the Azoic series is evi- 

 dence of the existence of life at the time of its formation. The same 

 view is also maintained with reference to the presence of graphite in 

 these rocks. In upholding these views it is the authority of Bischof 

 which is chiefly followed. This author, in his classic work on chemical 

 geology, declares in the most positive manner that those geologists who 

 believe that the earth has cooled from a condition of igneous fluidity can- 

 not do otherwise than admit that all the carbon on and in the earth is 

 of secondary origin, that is to say, was not present in the primeval earth 

 (inder Schopfungsperiode nicht vorhanden war). The statements which 

 he brings forward to sustain this view are, however,. not correct. 



The first of these alleged facts is, that carbon could not have existed 

 in contact with the oxides of iron and the other metals in a melted 

 magma, because it would necessarily have been oxidized to carbonic 

 acid and carbonic oxide.* In answer to this it may be stated, that, if 

 graphite cannot exist, it certainly can be formed, under these conditions, 

 since it is a well-known fact', daily witnessed by those engaged in blast- 

 furnace operations, that this material separates out in distinct crystal- 

 line plates and scales from the melted iron as it cools ; moreover, the 

 presence of graphite in furnace slags is a matter of not infrequent occur- 

 rence. The presence of graphite in the metallic iron meteorites may 

 also be mentioned in this connection, as strong evidence that carbon 

 can exist in connection with melted iron, or be in some way separated 

 from it. This graphite occurs in some cases in nodules completely 

 enveloped in the metallic mass. In the iron-bearing basalts of Green- 

 land, graphite is also found both in the metallic iron and in the basaltic 

 rock, in which this metal is cncloscd-t 



* Bischof, Jahrbuch der chcmischen und phy^lkaHschon Geologic, 2d edition, 



I. 662, 663. 



t See Tornehohra, in K. Svcnska Yet. Akad. Ilaiidlingar, Band V. No. 10 ; also, 



Daubree, Geologie Experimentale, p. 555. Lawrence Smith, Metnoire sur le Fer 

 Katif du Grocnlaiid, in Ann. de Chiin. et Phys., (5), XVI. 452-505. 



