GEOLOGICAL AGE OF PRINCE EDWARD ISLAND. WATSON. 147 



the North Mountain of Cornwallis and Annapolis counties. In 

 both Nova Scotia and New England the triassic age was remark- 

 able for the deposition of red sandstone in shallow bays and 

 straits, and for the ejection of great dykes of basaltic and 

 amygdaloidal basic volcanic ash. In Prince Edward Island, 

 "owing to the slight dips of the Permian and Triassic, and their 

 mineral similarity, it has proved difficult to define their boun- 

 daries; but the Trias appears to rest in slight troughs of the 

 Permian and to be partly composed of its rebris." 



Thus Dawson's accrediting to Prince Edward Island, beds of 

 Triassic origin was doubtless due to the opinion of Leidy 

 (endorsed by Cope) that the fossil, Bathygnathus borealis, 

 Leidy found at New London, was a dinosaur characteristic of 

 the Trias. In a letter to Francis Bain, Sir William wrote as 

 follows: "Look well to the north side of the island for the true 

 Trias." Bain was such an enthusiastic believer in the existence 

 of Triassic deposits in Prince Edward Island, that he con- 

 tributed to the Canadian Science Monthly, in 1885, an article, 

 entitled, "Bounding the Trias," in which he defines the supposed 

 limits of the formation, using, as a strong claim, the surface con- 

 figuration of the country. According to this writer, the surface 

 of the Permian districts is "like the gentle swelling of the sum- 

 mer sea," while that of the Triassic is "like a sea torn by the 

 wildest conflict of contending winds and currents." He further 

 defines the different characters of the sandstones of the two 

 systems : "The Triassic consists of thick-bedded sandstones, and 

 where rests on similar beds of the Middle Permian, it is diffi- 

 cult to distinguish between the two. But where it rests upon the 

 uppermost beds of shale and fissile sandstones, the distinction is 

 quite marked, and especially in scenic effect. . . . The Triassic 

 sandstones are distinguished from the Permian by having less 

 dark carbonaceous markings in them. There are fewer shales 

 and no calcareous conglomerates, although some of the sandstones 

 are indurated with lime. There are few well preserved fossils 

 in the system so far as we have yet discovered. My fieldbook 



