FERNS, FOSSILS AND FUEL 
than in the great Karoo formation of South Africa. 
It is also found in large deposits in Texas and in some 
other parts of North America, and it is prominent in 
Australia and in India. 
The plant life in the Karoo deposits showed plainly 
the influence of the ice cap which radiated from the South 
Pole during the period. The vegetation was considerably 
less than that of the Pennsylvanian period. A new 
fern-like plant became dominant in the southern hemis¬ 
phere, called the Glossopteris , or tongued fern, because 
its leaves were tongue-shaped. It was a rather small 
plant, with leaves attached to creeping stems. These 
stems looked like the human spine and were therefore 
called Vertebraria. The Glossopteris must have filled 
the plains and valleys like a weed or grass, for its leaf 
impressions are found everywhere throughout the Permian 
period in the southern hemisphere. It never penetrated 
to southern Europe or North America, but from India 
it entered the continent which at that time filled the 
place of the modern Ural Mountains and in this way 
penetrated far into the northern hemisphere. It was 
probably a seed fern, not a true fern. 
Some other fern-like genera of the Pennsylvanian 
period survive in the Permian Karoo, among them the 
Pecopteris and the Callipteridium. A new element 
76 
