MIOCENE PERIOD. 553 



fresh-water origin. Other Miocene deposits occur in Austria, 

 Germany, Switzerland, and the Siwalik hills in India. 



II. UPPER MIOCENE. The typical European deposits of 

 Upper Miocene age occur in the valley of the Loire, in France, 

 and are known as the " Faluns," a provincial term given to 

 shelly sands employed to spread upon soils which are deficient 

 in lime. The Faluns occur in scattered patches, which are 

 rarely more than 50 feet in thickness, and consist of sands 

 and marls. The fossils are chiefly marine, but there occur 

 also land and fresh-water shells, and the remains of numerous 

 Mammals. 



In Switzerland, between the Alps and the Jura, there occurs 

 a great series of Miocene deposits, known collectively as the 

 " Molasse," from the soft nature of a greenish sandstone, 

 which constitutes one of its chief members. It attains a thick- 

 ness of many thousands of feet, and rises into lofty mountains, 

 some of which as the Rigi are more than 6000 feet in 

 height. The middle portion of the Molasse is of marine 

 origin, and is shown by its fossils to be of the age of the 

 Faluns ; but the lower and upper portions of the formation 

 are mainly or entirely of fresh-water origin. The Lower 

 Molasse (of Lower Miocene age) has yielded about 500 species 

 of plants, mostly of tropical or sub-tropical forms. The Upper 

 Molasse has yielded about the same number of plants, with 

 about 900 species of Insects, such as wood-eating Beetles, 

 Water-beetles, White Ants, Dragon-flies, &c. 



MIOCENE OF NORTH AMERICA. Miocene deposits are 

 found in the United States in New Jersey, Maryland, Virginia, 

 California, Oregon, &c., and they attain sometimes a thickness 

 of 1500 feet. They consist chiefly of clays, sands, and sand- 

 stones: and in Virginia there is a bed of what is wrongly 

 called " Infusorial Earth," which attains a thickness of many 

 feet, and consists almost wholly of the siliceous cases of cer- 

 tain low forms of plants (Diatoms). The strata of the White 

 River, with remains of numerous Mammals, formerly spoken 

 of as Upper Eocene, are sometimes referred to the Miocene 

 formation. The fossils of the American Miocene are chiefly 

 Molluscs (of which 15 to 30 per cent are living species). 



LIFE OF THE MIOCENE PERIOD. The vegetation of the 

 Miocene period has been already spoken of, and need not be 

 again discussed here. The Invertebrates of the Miocene also 

 need no special mention, since they are very similar in type to 

 those now in existence, though mostly specifically distinct. 

 The Fishes, Reptiles, and Birds of the Miocene likewise call 

 for no special comment. The Miocene Mammals, on the 



