WB^ 



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NEW BBUNSWICIC. 



371 



pressly states tliat there is no proof of unconformability,* and also that 

 the deposits of the St. John group 



" present a uuirkcd contrast with those of the formation on which they rest 

 [Coldhrook Group]. Coarse fragmental beds and volcanic products are com- 

 mon in the latter ; but among the former no conglomerate or even a grit liaa 

 been detected, or any evidence of synchronic igneous action." (Quar. Jour. 

 Geol. Soc, 1865, XXI. p. 427.) 



It is also stated in the Observations on the Geology of Southern New 

 Brunswiek (18C5, p. 4G), that 



'' between the rocks above alluded to as constituting the upper member of the 

 Coldbrook Group, and the deposits which underlie the City of Saint John, thp 

 contrast is very marked. While in the former, beds of coarse materials are 

 almost universal, the Saint John Group is, without exception, a collection of 

 the fuier sediments. Throughout the limits of its distribution, not one con- 

 glomerate or even a grit has been yet observed ; while the. sandstones which 

 occur interstraiified with the slates, are usually of a fine and even texture." 



F 



If there were no conglomerates, or even grits, known in 1865 in the 

 St. John group, and the two formations were conformable, how could 

 Mr. Matthew, in the same paper in which these facts are stated, have 

 referred the Coldbrook group to the Huronian, because it was uncon- 

 formably overlain by the St. John group, and held fragments of the 

 Coldbrook group in its conglomerates^ The fact is, that Mr. Matthew, 

 at that time, assigned the Coldbrook group to the Huronian, on ac- 

 count of its lithologioal characters, and because it underlaid conform- 

 ably the St. John group. In fact Dr. Hunt himself was not aware 

 of any such unconformability of the rocks in question, since he thus 

 expressed himself in I8G6, referring to the Lower Silurian : — 



*' The lowest member of the series as yet known, is a group of 3000 feet of 

 black shales and sandstones, which at St. Johns, NeW Brunswick, is found 

 resting conformably upon still older schistose rocks, as yet unstudied. This, 

 which has been provisionally called the St. Johns group, has yielded numerous 

 fossils, which have been examined by Mr. Hartt, and show the formation to, 

 correspond with thti third division (Etage C) of the primordial zone." (Geol. 

 of Canada, 1800, pp. 235, 23G.) 



Lithologioal evidence, so far as we can find, is all that is offered in 

 support of the statement that the Bloomsbury group is "a repetition of 

 the Coldbrook group on the opposite side of a closely folded synclinal 

 holding Lower Cambrian sediments." The synclinal, the repetition, the 

 faults and overturns, appear to be purely theoretical, and introduced to 

 obtain conformity with that which the lithological characters seemed to 



* Sec Dawson's Acadian Geology, edition of 1808, pp. 600, 6G2. 



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