192 NEWER PLIOCENE STRATA [Ch. XIII 



origin above alluded to, was undergoing a slow upheaval, by which 

 those marine strata were raised to the height of 1200 feet above the 

 sea, as seen at Catera, and perhaps to greater heights, for we cannot 

 trace their extension westward owing to the dense and continuous 

 covering of modern lava under which they are buried. During the 

 gradual rise of these Newer Pliocene formations (consisting of clays, 

 sands, and basalts), other strata of Post-pliocene date, marine as well 

 as fluviatile, accumulated round- the base of the mountain, and these, 

 in their turn, partook of the upward movement, so that several inland 

 cliffs and terraces at low levels, due partly to the action of the sea and 

 partly to the river Simeto, originated in succession. 



Fossil remains of the elephant, and other extinct quadrupeds, have 

 been found in these Post-pliocene strata, associated with recent shells. 



Newer Pliocene strata of Sicily. — There is probably no part of Europe 

 where the Newer Pliocene formations enter so largely into the struc- 

 ture of the earth's crust, 01 rise to such heights above the level of the 

 r>ea, as Sicily. They cover nearly half the island, and near its centre, 

 at Castrogiovanni, reach an elevation of 3000 feet. They consist prin- 

 cipally of two divisions, the upper calcareous, and the lower argillaceous, 

 both of which may be seen at Syracuse, Girgenti, and Castrogiovanni. 



According to Philippi, to whom we are indebted for the best account 

 of the tertiary shells of this island, thirty-five species out of one hundred 

 and twenty-four obtained from the beds in central Sicily are extinct. 



A geologist, accustomed to see nearly all the Newer Pliocene forma- 

 tions in the north of Europe occupying low grounds and very incoher- 

 ent in texture, is naturally surprised to behold formations of the same 

 age so solid and stony, of such thickness, and attaining so great an 

 elevation above the level of the sea. 



The upper or calcareous member of this group in Sicily consists in 

 some places of a yellowish-white stone, like the Calcaire Grossier of 

 Paris ; in others, of a rock nearly as compact as marble. Its aggregate 

 thickness amounts sometimes to 700 or 800 feet. It usually occurs in 

 regular horizontal beds, and is occasionally intersected by deep valleys 

 such as those of Sortino and Pentalica, in which are numerous caverns. 

 The fossils are in every stage of preservation, from shells retaining por- 

 tions of their animal matter and color to others which are mere casts. 



The limestone passes downward into a sandstone and conglomer- 

 ate, below which is clay and blue marl, like that of the Subapen- 

 nine hills, from which perfect shells and corals may be disengaged. 

 The clay sometimes alternates with yellow sand. 



South of the plain of Catania is a region in which the tertiary beds are 

 intermixed with volcanic matter, which has been for the most part the 

 product of submarine eruptions. It appears that, while the clay, sand, 

 and yellow limestone before mentioned were in course of deposition at 

 the bottom of the sea, volcanoes burst out beneath the waters, like that 

 of Graham Island, in 1831, and these explosions recurred again and 

 a^ain at distant intervals of time. Volcanic ashes and sand were showered 



