Dr. Dawson — Geology of Prince EdwartTs Island. 205 



position of the Carboniferous on the Trias without the intervention 

 of the Permian. This is the more remarkable, as in Nova Scotia the 

 Triassic beds usually rest unconformably upon disturbed Carbonifer- 

 ous rocks. The anticlinals of the coal-fields of Nova Scotia and 

 New Brunswick, however, flatten out very much towards the coast, 

 and retaining the same attitude under Northumberland Strait, they 

 present very gentle inclinations under Prince Edward Island. 

 Hence only the higher beds of the Newer Coal-formation are seen, 

 and the Permian age having no representative, fossils alone indicate 

 the distinction of the Carboniferous and Triassic formations. The 

 beds seen in Prince Edward Island thus represent only a small 

 portion of the upper part of the Newer Coal-formation. They con- 

 tain no beds of coal, though trunks of carbonized trees appear in the 

 sandstones at G-allas Point ; and judging from the arrangement 

 observed in Nova Scotia, the upper coal-seams may be at a depth of 

 from 500 to 2000 feet. These coal-beds nevertheless underlie the 

 whole of Prince Edward Island, and may some day be reached. 



The most abundant fossil in the Newer Coal-formation of Prince 

 Edward Island is a coniferous tree of the genus Dadoxylon (Arau- 

 caroxylon) , and which I identify with my species D. materiarium, which 

 is extremely abundant in the upper sandstones of the Coal-formation 

 of Nova Scotia. These trees are mostly silicified, but specimens 

 also occur mineralized by carbonate of lime and per-oxide of iron, 

 and in a carbonized condition. The cracks formed by .decay in the 

 silicified specimens are often filled with a red variety of sulphate of 

 barium. In Nova Scotia a Walcliia or Araucarites (A. gracilis) pro- 

 bably represents the foliage of this tree, and the same species occurs 

 with it in Prince Edward Island, and also a second species of the 

 same genus. These Walchias may be regarded as Permian in 

 aspect ; but it must be remembered that there is every reason to 

 believe that the genus Walchia includes leafy branches ot Dadoxylon: 

 and the circumstance that in Europe the trunks are more character- 

 istic of the upper coal -formation and the branches of the Permian is 

 merely an accident of preservation. 



The other fossils found in these beds are the following. Those 

 marked with asterisks occur also in the upper coal-formation of Nova 

 Scotia : — 



*Pecopteris arborescens, Schlot. 



*P. rigida, Dawson. 



*P. oreopteroides ? Brongt. 



P. (allied to P. Goepperti, Brongt.) 



* Alethopteris nervosa, Brongt. 



A., massilionis, Lesqux. 



*Neuropteris rarinervis, Bunbury. 



* Cordaites simplex, Dawson. 



*Calamites Suckovii, Brongt. 



*G. Sistii, Brongt. 



C. gigas, Brongt. 



C. arenaceus ? Jaeger. 



Trigonocarpum, sp. 



This may be regarded as on the whole an assemblage characteristic 

 of the newest beds of the Upper Coal-formation. Several of the 

 species are in Europe common to the Carboniferous and Permian ; 

 but none of them are exclusively Permian. The beds containino- 

 such fossils constitute the newest members of the Carboniferous both 

 in Nova Scotia and in Europe. 



The superficial deposits of Prince Edward Island consist of 



