88 THE TRIAS OR NEW RED SANDSTONE. 



a somewhat tough rock. Modern tufa, quite analogous to that of the 

 trap, is very abundant in volcanic countries, and sometimes sufficiently 

 hard to be quarried as a stone. 



As the new red sandstone and trap are formations of one period, 

 and differ only in origin, it will be convenient to consider them 

 together. I shall therefore proceed to describe these two rocks as 

 they appear in connexion in different parts of Nova Scotia, New 

 Brunswick, and Prince Edward Island, and then notice their fossil 

 remains and useful or interesting minerals. 



1. Truro and South Side of Cobequid Bay. 



In the valley of the Salmon River, four and a half miles eastward of 

 the village of Truro, the eastern extremity of the New Red Sandstone 

 is seen to rest unconformably on hard reddish brown sandstones and 

 shales, belonging to the lower part of the Carboniferous system, and 

 dipping N. 80° E. at an angle of 40°. At this place the overlying 

 formation is nearly horizontal, and consists of soft and rather coarse 

 bright red silicious sandstones. Southward of Truro, at the distance 

 of less than a mile, the horizontal soft red sandstone is seen, in the 

 banks of a brook, to run against hard brownish grits and shales, 

 dipping to the eastward at angles varying from 45° to 50°. Westward 

 of this place, the red sandstones extend in a narrow band, about a 

 mile in width, to the mouth of the Shubenacadie, ten miles distant. 

 This band is bounded on the north by Cobequid Bay, and on the south 

 by highly inclined sandstone, shale, and limestone of the Lower 

 Carboniferous series. In the coast-section, between Truro and the 

 Shubenacadie, the red sandstone presents the same characters as at 

 the former place, except that, near the Shubenacadie, some of the beds, 

 which, like most of the red sandstones of Truro, have a calcareous 

 cement, show a tendency to arrangement in large concretionary balls. 



West of the mouth of the Shubenacadie, the red sandstone ceases 

 to form a continuous belt, but occurs in several patches, especially at 

 Salter's Head, Barncote, and Walton. At the latter place, it is seen 

 to rest on the edges of sandstones and other rocks of the Lower 

 Carboniferous system, affording a very fine example of that unconform- 

 able superposition which in geology proves the underlying formation 

 to have been elevated and disturbed before the overlying beds were 

 deposited upon it. This appearance is represented in Fig. 25, and 

 was thus described by the writer in a note supplementary to his paper 

 on the New Red Sandstone of Nova Scotia, and communicated to the 

 Geological Society in 1852 : — 





