6 THE ROYAL SOCIETY OF CANADA 
cursors of the Reptilia of a later date, we have at this stage of the 
Carboniferous fishes whose remains are found in the deeper water 
deposits. 
The Stegocephalians belong mainly to the Microsaurian branch of 
the Lepospondyli and to the Labyrinthodontia, and comprise species 
belonging to as many asnine genera. Our knowledge of these particular 
forms is due principally to the genius of the late Sir J. William Dawson 
who recognized the importance of the remains found by him in the 
stumps of fossil trees at South Joggins, Nova Scotia, and devoted 
much time to the elucidation of the characters of the species then 
brought to light. The establishment of the Microsauria as a distinct 
division of the Stegocephalia was due to him. Many tracks also, 
generally ascribed to batrachia, occur at South Joggins, and at Sydney, 
N.S., and have been described by Dawson and Matthew. 
The fishes are Elasmobranchs, Dipnoans and Crossopterygian 
Teleostomes. Among the Elasmobranchs are Dittodus representing 
the Pleuracanthidæ, and the two Selachian forms Ctenoptychius and 
Psammodus. To the Dipnoans belongs the single Sirenoid genus Con- 
chodus, whilst the Crossopterygians include such genera as Rhizodus, 
Strepsodus and Parabatrachus. 
In the strata of the next geological period, that of the Permian as 
developed in Prince Edward island, was found the portion of the head 
of the Rhynchocephalian reptile described in 1854 by Leidy as the 
mandibular ramus of a Triassic dinosaur under the name Bathygnathus 
borealis. In 1876, in the Quarterly Journal of the Geological Society, 
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 independently recognized its true 
position in the Pelycosauria but its exact generic affinities are still in 
doubt. This specimen, from Prince Edward island, was found near New 
London, and on the strength of its supposed dinosaurian nature the 
beds from which it came were for some years considered to be of Triassic 
age although the rocks of the remainder and major portion of the island 
were regarded as Permian. The Pelycosauria are typical of the Permian 
so that any doubt as to the age of the beds from which Bathygnathus 
borealis came has been removed. This primitive Rhynchocephalian is 
the earliest reptile of which any trace has been found in this country, 
and is the only vertebrate known from the Permian of Canada. It may 
be mentioned here that the now existing Sphenodon of New Zealand is 
the sole survivor of the Ryhnchocephalian order. 
We now come to a very decided break in the continuity of vertebrate 
life in this country, so far as our knowledge of it is concerned, as no 
vertebrate remains have been found in rocks of Triassic and Jurassic 
