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KlilSUMlS, AND GKNEKAL DISCUSSION. 



527 



The original crust of the earth must have been azoic, if we adopt the 

 views held by the large majority of geologists, that our globe has cooled 

 from a former condition of igneous fluidity. The volcanic and eruptive 

 rocks must necessarily be azoic, because they have come from the heated 

 interior of the globe, reaching the surface, for the most part, in a melted 

 condition. We do not, however, designate the eruptive and volcanic 

 rocks as "Azoic"; the fact that they are necessarily in this condition is 

 assumed as something self-evident. 



4th. We may have rocks formed under such conditions as were not 

 inimical to life, but yet azoic, because life had not begun to exist on the 

 globe at the time of their deposition. These, according to our view, 

 would be the rocks properly designated by the term " Azoic," and the 

 body of rocks having this character might properly be called the 

 ** Azoic System." And we think that, in view of what has here been 

 set forth, no one will deny that it is important that, if there are such 

 rocks, they should have a special designation, and that the term 

 *' Azoic" would be a proper one to apply to them. 



This, however, is exactly what was done by Foster and Whitney, 

 in 1850, when they gave the name of the "Azoic System" to a body of 

 strata, originally — in part, at least — of sedimentary origin, which did 

 not show by their character that life could not have existed at the time 

 of their deposition, but which proved, on examination, to be entirely 

 destitute of fossils, and which, moreover, were found everywhere to 

 underlie unconformably other sti-atificd formations which were recog- 

 nized as containing the lowest known forms of organic life. 



Over thirty years have elapsed since these rocks were designated as 

 forming the Azoic System, and the point at present at issue is, wliether 

 anything has been discovered in geology which renders this designation 

 improper, unnecessary, or undesirable, or which justifies the adoption of 

 either one of the terms "Laurentian " or "Archaiau," or both, the ques- 

 tion of the propriety of dividing the Azoic System into two or more 

 groups being one to be examined farther on. 



The introduction of the name *' Laurcntian " by the geologists of the 

 Canada Survey has been already commented on, and it has been shown 

 that this term, as first used by Mr. Logan, was the exact equivalent of 

 the Azoic of Foster and Whitney. That being the case, the question 

 of the propriety of this action on the part of the author of the new 

 designation may be left to the good sense of the reader, who will judge 

 for himself whether replacing a designation already in use by another 

 one, previouslv employed by another geologist with a totally difTorent 



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