[ells] CAMBRIAN ROCKS OF SOUTHERN NEW BRUNSWICK US 



but occasionally overlies the Kingston and Coldbrook, while in the 

 west part of St. John city, as at the suspension bridge, the upper or 

 Bretonian division of the Cambrian is in contact with the limestone, 

 quartzite and slates which have been regarded as belonging to the 

 upper Laurentian series. This is the series which is at present of 

 special interest from the geological standpoint; and the contact of 

 the Bretonian is marked by a fault which extends from the end of 

 the suspension bridge eastward along what is known as the strait 

 shore. 



This age of the upper Laurentian division was assumed by Drs. 

 Bailey and Matthew, and supported in part by Sir William Dawson, 

 partly on lithological grounds and partly from finding in portions of 

 the limestone certain peculiar forms supposed to be organic in char- 

 acter, and to be related to the form known as Eozoon, which occurs 

 in the Grenville series of Quebec and the Hastings series of Ontario. 

 In southern New Brunswick it received the name, given by Matthew, 

 of Archffiozoon. The history of this supposed Laurentian organism 

 is somewhat interesting, and as it has a somewhat important bearing 

 on the original interpretation of the structure of the St. John rocks 

 may be here briefly stated. 



The peculiar form known as Eozoon was first found in Quebec 

 nearly fifty years ago, associated with the upper Laurentian formation 

 north of the Ottawa river, and shortly after somewhat similar forms 

 were recognized in eastern Ontario. It was chiefly studied by the 

 late Sir William Dawson, and was supposed to represent the earliest 

 known form of life. In the course of investigation on these old rocks 

 of Ontario and Quebec, where this form was principally recognized, 

 it was ascertained that as regards the Ontario specimens, the organic 

 nature of the supposed fossil could not be maintained, since the speci- 

 mens known as the Tudor and Burgess Eozoon were closely and 

 clearly associated with igneous rocks which occurred as dikes cutting 

 the crystalline limestone, and the supposed organism owed its peculiar 

 structure to forms developed in the intrusive portions, which were 

 diabasic in character, rather than to occurrences in the limestone itself. 



In course of time, therefore, the contention as to the organic 

 nature of these forms from Ontario was gradually abandoned, but 

 the organic nature of the Quebec specimens was still maintained, 

 chiefly by Sir William Dawson. The best specimens of Eozoon were 

 found principally in a quarry at Côte St. Pierre, about forty miles 

 east of Ottawa. A subsequent critical examination of this locality 

 clearly shewed that in this case also, the Eozoon structure was due 

 to the association with igneous rocks, principally a gabbro diorite, 

 with limestone. The quarry was originally opened in a serpentinized 



