232 



that the highest strata are present only on Prince Edward 

 Island. In the New Glasgow area the total thickness of 

 the strata is very great. In the case of one section, a 

 detailed estimate by Fletcher [8, p. 114] gives a thickness of 

 above 8,000 feet (2,440 m.) chiefly sandstones, and shales, 

 overlying a basal series of conglomerates, etc., of undeter- 

 mined thickness but presumably not less than 1,000 feet 

 (300 m.). In the case of a second section [8, p. 117] 

 measured a few miles to the west of the first, the thickness 

 including the conglomerate strata at the base, amounts to 

 slightly over 5,000 feet (1,520 m.). The difference in the 

 total estimated thickness of the two adjoining sections is in 

 part accounted for by the presence of a fault in the case of 

 the section with the smaller total. However, having regard 

 to the character of the strata, it is reasonable to suppose 

 that the total thickness may vary rapidly from place to 

 place. In view of what has been stated it may be concluded 

 that the total thickness of the whole group is not less than 

 10,000 feet (3,000 m.). 



The age of the group in general, depends upon the 

 finding of reptilian remains in what are supposed to be the 

 highest strata of the group on Prince Edward Island; and 

 on the palseobotanical studies of Dawson. The facts of 

 the case in connection with the reptilian remains have been 

 summed up by Lambe [10] as follows: — The fossil remains 

 found, consist of a "portion of the head of the Rhyncho- 

 cephalian reptile (which was) described in 1854 by Leidy as 

 the mandibular ramus of a Triassic dinosaur under the name 



Bathygnathiis borealis. In 1876, , Sir Richard 



Owen drew attention to the fact that the specimen apper- 

 tained in reality to the upper jaw and referred it to the 

 Theriodontia. Later in 1905, v. Huene and Case inde- 

 pendently recognized its true position in the Pelycosauria 



but its exact generic affinities are still in doubt 



The Pelycosauria are typical of the Permian." 



The following tabulation of the plants recovered from the 

 Permo-Carboniferous is based on one prepared by Dawson 

 [4] with the addition of a few species which Dawson believed 

 came from Triassic measures on Prince Edward Island [3]. 



