26 A SUMMER IN GREENLAND 
The cliffs on some parts of the coast are built up 
of limestones, sandstones, shales, and old pebble 
beaches containing the remains of animals and 
plants characteristic of several geological periods 
and clearly indicating climatic conditions within 
the Arctic Circle much more genial than those at 
the present day. Even in the extreme north, on 
the shore of the Polar Sea, limestone rocks have 
been described by the Danish geologist, Koch, as 
veritable coral reefs of the Palaeozoic era. 
The most northerly point at which fossil plants 
have been found is on the east coast of Greenland, 
between lat. 80° N. and 81° N. Fragmentary re- 
mains of plants were found by the Denmark 
Expedition of 1906-1908: these were described 
by the late Professor Nathorst, who recognised 
them as members of a flora which preceded that 
of our Coal Measures. The locality where these 
plants were found is nearer to the North Pole 
than any previously recorded for Carboniferous 
plants. 
Greenland is a mountainous plateau mainly com- 
posed of some of the oldest rocks in the world 
belonging to a stage in the history of the earth (the 
Archaean period) which is shrouded in mystery: 
of the life of this period we have no certain know- 
ledge. On the extreme northern coast, also at 
many places on the east and west coasts, the 
presence of thick series of ancient sediments and 
of rocks consisting of accumulated masses of the 
calcareous skeletons of marine animals is evidence 
of recurrent subsidences of the land and the sub- 
