PHYSICAL HISTORY OF NEW HAMPSHIRE. 5 T I 



The terms Azoic, without life, and Hypozoic, beneath life, are still applicable to the 

 stratigraphical systems which flourished antecedently to the Laurentian, but they are 

 not appropriate designations for any of the crystalline strata which are now referred to 

 the Eozoic. If it be objected that many will still understand these terms in their 

 former acceptation, it may be answered, that, when properly informed, such persons 

 will more easily understand the shifting of the designation than the proposal of a new 

 name. For the past twenty-five years many groups of strata had been removed from 

 the Azoic system without giving rise to any misunderstanding. Furthermore, no one 

 is yet able to point to any locality where these most ancient systems crop out ; hence 

 the liability to misconception is greatly reduced. The Azoic rocks, as now under- 

 stood, are limited at their top by the Laurentian system, and at the bottom by the very 

 beginning of deposition. If we grant the existence of animals in the Laurentian, and 

 follow out the analogies derived from the development of the higher from the lower 

 forms of life, animals succeeding plants, then there must have been an immensely 

 long period antecedent to the Laurentian, characterized as the Eophytic, or the dawn 

 of plant-life. This system, if ever discovered, will be entitled to a place by the side 

 of the four great divisions specified above. 



The name Eozoic seems to have been proposed by Dr. J. W. Dawson, of Mon- 

 treal, in 1865. He did not fully define the limits of its application at that time ; but it 

 seems to have been generally understood by geologists to embrace all the obscurely 

 fossiliferous rocks older than the Cambrian. The considerations just stated, showing 

 that our crystalline rocks contain obscure evidences of life, make it plain that the 

 Eozoic system is a natural one, characterized by very scanty traces of organisms. Its 

 separation, as a system, from those beneath entirely devoid of life, is also natural, and 

 in accordance with the most approved geological usage.* 



The First Dry Land in New Hampshire. 



Accepting as a fact the doctrine that the whole globe was entirely 

 covered over by the ocean before the beginning of the deposition of 



* The recent proposal by Prof. J. D. Dana, in the second edition of his Manual of Geology, to call both the 

 Azoic and Eozoic systems Archaan, the bcginni7tg rocks, seems uncalled for, but would be less objectionable if 

 the author's own definition was strictly adhered to. The distinctions given between the Azoic and Eozoic are 

 not incompatible with those stated in the text above ; but the v/ord Arch&an is nearly universally used in the sense 

 of Eozoic throughout the Manual. On page 140, in giving the subdivisions of all geological time, he says, 

 " Akch.eAn Time, including an Azoic and an Eozoic era, though not yet distinguished in the rocks. 1. Azoic 

 Age. 2. Eozoic Age." On page 148, reference is made to Dawson's suggestion of the word Eozoic in place of 

 Azoic, with the opinion that its use is objectionable, because the supposed Eozoon may be of mineral nature. 

 On page 151, the Archeean Era is divided into the two periods, Laurentian and Huronian. The word Archaean, 

 on page 151, seems to be synonymous with Eozoic, on page 140. I do not suppose the use of the word Eozoic 

 implies belief in the existence of the animal Eozoon. The adjective to be used in that sense would be Eozoonal. 

 The distinction between the true Azoic and Eozoic ages is of greater import than between any other two of those 

 used to mark geological time ; and hence the union of them under one designation is uncalled for. Furthermore, 

 Dawson's name has the advantage of several years' prior suggestion and general usage among geologists. It is 

 also undesirable to break up the unity of the terminology of the great ages of the world's history by adopting a 

 term not having the termination of zoic. For these and other reasons, it does not seem to be for the good of the 

 science to substitute Arcruean for Eozoic in geological literature. 



