450 



THE AZOIC HYSTEM AND ITS SUBDIVISIONS. 



(Mr. Hunt) to propose for it [the year before] the name of the Terranovan 

 System. At this point in the Address there is a reference to this Journal of 

 the preceding year, Vol. L, p. 87, 1870 ; and consequently by referring back 

 to this article by Mr. Hunt, I found this Terranovan delined, Mr. Hunt saying 

 thatj according to Mr. Murray, the series comprises 'several thousand feet (if 

 strata, including soft bluish gray mica slates and micaceous limestones belong- 

 ing to the Potadarn, group, besides a great mass of whitish granitoid mica slates 

 whose relation to the Potsdua is still uncertain/ As the Huronian is older 

 than the Potsdam, and this ec|uivaleucy of the Terranovan is not corrected in 

 the Address, I thought I had reason for supposing that Mr. Hunt made the 

 White Mountain series the newer. I acknowledge I prefer the view he now 

 presents, since the less definite the statement the better as long as we have no 

 sufficient facts for a conclusion." (Am. Jour. Sci., 1872, (3) IV., p. 105.) 



Our extracts taken from Dr. Hunt's Address * show, however, that 

 ho did make the White Mountain series younger than the Green Moun- 

 tain series, and that Professor Dana was correct. Furthermore, it will 

 be shown that Dr. Hunt had advocated this view some time previous to 

 his delivery of the Address ; and that later Lc claimed to have advo- 

 cated this order of age at the time of the Address and previously. The 

 reader's attention is also called to the fact that in Dr. Hunt's Chemical 

 and Geological Essays (p. 32G) the sentence, ^' A careful perusal of my 

 address will show that I nowhere assert that the rocks of the third 

 scries (Moutalljaii), on my lino of section, are younger than the second 

 series " (Huronian), is expunged, although the paper purports to be a 

 reprint of his reply to Professor Dana. 



It is possible that the reader will find the reason for this expurgation 

 in what follows. On May 1, 1871, some three and a half mouths be- 

 fore the Address was given, Dr. Hunt said : 



^^ In d. (lomm^xmQ.^X\on io i\i(i Bodon Natural Ilistory Society on the 19th of 

 October lust, and subsequently in the American J ouriial of Science iov February 

 and March, 1871 ([)ages 84 and 182), I have expressed the opinion Ihat the 

 porphyries .... are stratihed rocks, belonging .... to the Huronian sys- 

 tem, or Green Mountain system I have in tliat same journal for July, 



1870, pointed out the fact that the Eozoon of Hastings county, Ontario, occurs 

 in a series of crystalline schists which I consider newer than the Iluruin'an, 

 and the erpiivalent of tlie White Mountain gneisses and mica schists." (Bulk 

 Essex Institute, 1871, III, pp. 53, 54.) 



Dr. Hunt's remarl^s, published in the Proccodrngs of the Boston 

 Society of Natural History to which he above refers, are as follows :. 

 " I regard these two types of rocks ((piart;^o-feldspathic rocks and dioritic 



* Sou ante^ p. 417. 



