C. Schuchert — Pre-Cambrian Nomenclature. 483 



must cover two or more groups itself; it must be of the same 

 rank with Paleozoic, Mesozoic and Cenozoic." 



"The new term should have some reference to the life- 

 conditions of these early times." It " should then express the 

 existence of this early life, and our present ignorance with 

 regard to its nature." Many new terms and one old one were 

 considered by Irving. Among these was Proterozoic, a term 

 suggested by Mr. Emmons; while the name is "simple and 

 made from a Greek word of not too uncommon use, [it] seemed 

 to fail in covering the ground sufficiently. I have therefore 

 been disposed to return to a term early proposed by Professor 

 T. C. Chamberlin. ... I would advocate therefore the use 

 of the term Agnotozoic (unknown life), to cover all of the 

 geological interval lying between the base of the Cambrian 

 and the summit of the Archean crystallines." 



" It is suggested therefore that the term Archean be used to 

 cover only the pre-Huronian basement crystallines ; that the 

 Cambrian group remain as the basal member of the Paleozoic 

 System, and that the new system name Agnotozoic ... be 

 used to cover, at least provisionally, such clastic groups as inter- 

 vene between the Cambrian base and the Archean schists." 



In another place* Irving writes : " It seems, therefore, 

 desirable that a new term should be introduced of equal classi- 

 h'catory rank with Paleozoic, indicating that these great Pre- 

 Cambrian and Post-Archean series are zoic in character, and 

 that they cannot, as yet at least, be admitted to the Paleozoic 

 series proper. ... I advocated the adoption of the term 

 Agnotozoic, indicating at once the presence of life and its 

 unknown character." 



As stated beyond, Irving credits the first use of the term 

 Agnotozoic to Chamberlin, but the latter writes, f " Although 

 I have used the term in correspondence, conversation, discus- 

 sion, and other informal ways for the past two years, more or 

 less, I have nowhere formally proposed it in a scientific publi- 

 cation." Through first publication therefore the name belongs 

 to Irving. 



In this connection it is best also to give the conclusion of 

 Van Hise^:, who says: "It is imperative that some term shall 

 be available to cover the great mass of rocks between the 

 Cambrian and Archean. Irving was the first to realize and 

 urge the necessity for such a term and proposed for it Agnoto- 

 zoic. This term implies the existence of life in this system, 

 and the evidence upon this point is conclusive." 



" The clastic rock masses below the Olenellus fauna are so 

 enormous that the proposal to introduce a general term like 



♦Seventh Ann. Eep. U. S. Geol. Surv., 1888, 453-454. 



t This Journal, (3) xxxv, 254, 1888. 



{Bull. 86, U.'S. Geol. Surv., 1892, 491, 493. 



