590 THE MIOCENE PERIOD 



along the north base of the Alps, and tell something of the relief of 

 the Alpine region at the time. Southern Europe appears to have 

 been an extensive archipelago, the plateau of Spain, parts of the 

 Pyrenees, the Alps, and the Carpathian Mountains, and portions of 

 adjacent lands being islands. The sea of southern Europe extended 

 east far beyond the limits of the present Mediterranean, but late in 

 the period it was much restricted. 



The Miocene formations include all the common sorts of sedi- 

 mentary rocks common to marine and non-marine deposits. The 

 latter include not a little limestone of fresh-water origin, made 

 partly from the secretions of algae. In Italy the system is said to 

 have a thickness of nearly 6,000 feet. 



Considerable disturbances occurred in the later part of the 

 period, and at its close. Before its end, the Alps had had a period 

 of growth, usually placed at the close of the Lower Miocene. The 

 Apennines and other mountains of southern Europe also were in 

 process of development during the later Miocene. In the Caucasus 

 Mountains, Miocene beds occur up to heights of 2,000 meters. As 

 in America, widespread movements which were not notably 

 deformative attended the growth of the mountains, with the result 

 that the sea which had overspread southern Europe was greatly 

 restricted, though not reduced to its present size. Igneous activity 

 appears to have attended the movements, but not on such a scale 

 as in North America. 



Other continents. The Miocene of Asia has not been generally 

 separated from the other Tertiary formations, but is known to be 

 widely distributed in the southern part of the continent. In 

 Africa, Miocene formations occur in Algeria and Lower Egypt, and 

 are well represented in Australia and New Zealand. The beds are 

 found up to heights of 4,000 feet, giving some clue to the extent of 

 post-Miocene crustal deformation here. 



In South America, Miocene beds probably occur on the western 

 coast, and are known to have extensive development on the eastern 

 plains of the southern part of the continent, 1 where the distinction 

 between Upper Oligocene and Miocene is not sharp. The lower part 

 of the Oligocene-Miocene series (Patagonian beds) is marine, while 

 the upper part (Santa Cruz) is of fresh- water origin. The terrestrial 



1 Hatcher, Sedimentary Rocks of Southern Patagonia, Am. Jour, of Science, 

 Vol. IX, 1900; and Ortmann, Princeton Univ. Repts. of Expedition to Patagonia, 

 Vol. IV, Pt. II. 



