DEVONIAN LIFE 399 



ancient periods. These strata were laid down in closed basins 

 (sometimes, perhaps, in fresh-water lakes), which had only a 

 restricted communication with the sea. The Old Red is found 

 in south Wales and the adjoining part of England, and, on a 

 much larger scale, in Scotland ; also in the Baltic provinces of 

 Russia, where the fossils are mingled with those of the marine 

 Devonian ; in Spitzbergen and Greenland the same formation 

 recurs. These sandstones are said to be 10,000 feet thick, but 

 according to some authorities, the lowermost part of them is 

 Silurian. The so-called Catskill of New York is very like the 

 Old Red, and contains similar fossils. 



The European Devonian is full of the evidences of volcanic 

 activity, in the shape of great lava flows and tuffs. In central Scot- 

 land the volcanic accumulations exceed 6000 feet in thickness. 



Besides the Devonian areas already mentioned in Asia, rocks 

 of this system are found in China, the Altai, and in Asia Minor. 

 They recur in northern and southern Africa, being the most 

 ancient Palaeozoic rocks yet reported from the latter region. In 

 South America occurred a great transgression of the sea, and 

 Devonian strata form larger areas of the surface than those of 

 any other Palaeozoic system. Shallow-water deposits are found 

 in Bolivia, over large parts of Brazil, especially the basin of the 

 Amazon, and in the Falkland Islands. The Bolivian Devonian, 

 which belongs to the lower and middle parts of the system, con- 

 tains a very similar fauna to that of North America and connects 

 the latter with Brazil, the Falkland Islands, and south Africa. 



Devonian Life 



The life of the Devonian is, in its larger outlines, very like that 

 of the Silurian, but with many significant differences, which are 

 due, on the one hand, to the dying out of several of the older 

 groups of animals, and, on the other, to the great expansion of 

 forms which in the Silurian had played but a subordinate role. 



Plants. — The fossils show that in Devonian times the land was 

 already clothed with a varied, rich, and luxuriant vegetation of the 



