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 " quartziferous feldspar-porphyries " of East- 

 port, which Dr. Himt 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 wei'e. 



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

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

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

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

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

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

 Association (Proceedings, XX. p. 33), Dr. Hvmt claimed that in the above- 

 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-Cambrian in age, and 

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

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

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

 maquoddy Bay were Huronian. 



According then to the original paper, and to Dr. Hunt's subsequent 

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



The felsites were Cambrian. 



The felsites were Huronian. 



The Huronian was pre-Cambrian. 



The Terranovan was post-Huronian. 



The Terranovan was pre-Cambrian. 



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



The geological relations of the Terranovan to the felsites 



WERE unknown. 



From this table of conflicting views the student of North American 

 geolog}' can draw his own conclusions as to the value of the work done 

 on a basis of lithological classification and speculation. 



