372 



THE AZOIC SYSTEM AND ITS SUBDIVISIONS. 



demand. Had not these rocks resembled the Huronian, no one would 

 have ever thought that they were not Devonian ; but here appeared to 

 be some discrepancy in the theory of Delesse and David Forbes, adopted 

 by Dr. Hunt, that certain rocks could have appeared only at one epoch 

 in the earth's history, and to get over this difficulty an overturn of the 

 strata was claimed. The *' quart^iferous feldspar-porphyries " of East- 

 port, which Dr. Hunt has here placed under the Huronian, have since 

 been shown by Bailey to be at least as recent as the Upper Silurian, 

 since they rest nearly horizontally upon Upper Silurian fossiliferous sand- 

 stone. In fact, on comparing Dr. Hunt's published views in 1870 with 

 his explanation of them since given, it becomes quite impossible to make 



out what those views really were. 



In 1870 the Coldbrook group, to which he assigned the felsitcs, was 

 spoken of as Cambrian. (Am. Jour. Sci., 1870, (2) L. p. 89.) This paper 

 related principally to the Terranovan, since called Montalban, and later 

 separated into the Montalban and Taconian. The Terranovan at that time 

 was regarded by Dr. Hunt as being in part Potsdam, and its relations 

 to the felsitcs unknown. In 1871, in his address before the American 



r 



Association (Proceedings, XX. p. 33), Dr. Hunt claimed that in the.abovc- 

 quoted paper of 1870 he held that the Terranovan was more recent than 

 the Huronian. In 1872, in his " History of the Names Cambrian and 

 Silurian in Geology," he claims to have held, since 1870, that the Ter- 

 ranovan (Montalban) and Huronian were pre-Cambriau in age, and 

 refers to the same paper for proof of this. (Canadian Nat., 1872, (2) 

 VI. p. 435.) In his "Azoic Eocks" (pp. 189-193) he claims to have 

 held since 1870, referring to the same paper, that the felsitcs of Passa- 



maquoddy Bay were Huronian. 



According then to the original paper, and to Dr. Hunt*8 subsequent 

 explanation of it, he maintained in 1870, in the same paper, that 



The FBLSiTBS WERE Cambrian. 



The FELSITE3 AVERE IIURONIAN. 



The IIu[l0^fIAN was pre-Cambrtan. 



The Terranovan was post-Huronian. 



The Terranovan was pre-Cambrian. 



The Terranovan was in part (several thousand feet) Potsdam. 



The geoeogioal relations of the Terranovan to the felsites 



WERE unknown. 



From this table of conflicting views the student of North American 

 geology can draw his own conclusions as to the yalue of the work done 

 on a basis of lithological classification and speculation. 



