8 NEW YORK STATF. MUSEUM 



A glance at the map will enable the reader to perceive, extending south- 

 west from Bathurst, in the Bay de Chaleur, that broad and rugged belt of 

 altered Lower Silurian and plutonic rocks, the terror of railway engineers, 

 which forms the natural limit of Acadia on the northwest, and separates the 

 coal field of New Brunswick from the Upper Silurian valley of the Resti- 

 gouche and Upper St John, the debatable land, in point of physical geog- 

 raphy, between the high lands of the Nepisiguit which belong to New 

 Brunswick, and the high lands of Rimouski and Gaspe which belong to the 

 Province of Quebec. 



This belt of very ancient rocks was probably a physical barrier even as 

 early as the Upper Silurian period ; for on passing it we find in the valleys 



View of Stewart's cove looking south from near the Bon Ami rocks. The low terrace embraces only 

 the upper division of the scries. The hill in the middle distance is an interbedded intrusive 

 mass beyond which in a shore retreat the rest of the series is concealed. 



of the Restigouche and the neighboring streams, beds of highly calcareous 

 and fossiliferous Upper Silurian rocks identical in character with those of 

 Gaspe, and differing both in mineral character and the assemblage of fossils 

 from those which we have just been studying. The southern limit of this 

 1 pper Silurian area, in so far as it is known, may be seen on the map ; and 

 its structure may be learned from the following description by Professor 

 Mind of the section at Cape Bon Ami [Stewart's cove] near Dalhousie. 

 The section is in ascending order, and the dips are to the northward at an 

 angle of 45 . 



1 Trap. 



2 Calcareous shales. 



3 Trap or trappean ash, more or less stratified, and with veins of car- 

 bonate of lime and quartz. 



4 Calcareous shales and honestones, weathering buff or pale yellow. 



