PERMIAN REPTILES OF SOUTH AFRICA AND RUSSIA 729 
The thicknesses of the various zones are only very approximate 
and vary considerably in different parts of the country. The 
Burghersdorp beds contain the following European genera Tremato- 
saurus ,* Cyclotosaurus, Capitosaurus, besides others allied to Euro- 
pean Triassic forms and there can be no doubt that the beds are 
of Upper Triassic age. The Lystrosaurus and Procolophon zones 
may be regarded as corresponding to the Lower Triassic of Europe, 
though we have no genera corresponding to those of Europe. 
All the zones from the Cistecephalus to the Droyha may be 
taken as representing the European Permian, and this is con- 
firmed by the fact that the Russian ‘‘Pareiasaurus’’ zone corre- 
sponds, not with our Parezasaurus zone, but with our Cistecephalus 
zone. 
Anyone who is familiar with our typical South African Pareia- 
saurus and then looks at the Dwina Pareiasaurs will at once see 
that the resemblance is not striking; and had I found the Russian 
species at the Cape, I should have put it in a new genus probably. 
Just recently a new Pareiasaurian was discovered by Haughton in 
the Cistecephalus zone, and it has been described by Haughton and 
myself as a new genus, Paretasuchus peringaeyi, and we have called 
attention to the fact that it resembles the Russian animals much 
more than does our older Pareiasaurus. But of much more impor- 
tance than the doubtful Pareiasaurus is the Russian Inostrausewia. 
This is a huge carnivorous reptile something like our carnivorous 
types. But no known Therocephalians from our Pareiasaurus zone 
are the least like [nostrausewia. 
Just recently we have got evidence that our Permian carnivora 
can be conveniently subdivided into two groups. The lower forms 
are the typical Therocephalians: the upper I am placing in a dis- 
tinct group, the Gorgonopsia. It matters little whether this be 
regarded as a distinct family or suborder. I prefer to call it a dis- 
tinct suborder. A paper is at present in the press dealing with the 
distinction of the groups. Though our small Gorgonopsian is 
known from the Pareiasaurus zone, it is in the Cistecephalus zone 
that the group becomes pre-eminent. A large South African type 
recently described as Scymnognathus tigriceps is possibly identical 
«Tt is just possible Trematosaurus may be from the Lystrosaurus zone. 
