186 GEOGNCSY AND GEOLOGY. 
The series is closed by a deposit of sand, sandstones, and marl, of marine 
origin, and containing Ostrea (O. flabellula especially), fishes, &c. In the 
sand there is found the so-called crystallized sandstone of Fontainebleau, 
which, however, in reality it is not. It consists of an aggregation “of 
rhombohedrons like those of calcareous spar; in fact, these crystals are 
only carbonate of lime mixed up with sand. It is a little remarkable that 
the force of crystallization should have been great enough to overcome 
these impurities. 
The Paris tertiary basin rests upon the cretaceous. Pl. 44, fig. 6, 
exhibits a map of it, in which its distribution may be more readily 
followed. Fig. 7 is a section of the same. The line a indicates the level 
of the sea, 1 the tertiary, 2 the cretaceous, and 3 the Jurassic strata. 
The London tertiary basin exhibits certain features distinguishing it 
from that of Paris; while in the latter, limestone masses entered in 
considerable prominence, in the former, clays and marls predominate. 
The bone gypsum is entirely wanting. The masses occur in the following 
order : 
Beneath lies a plastic clay very rich in fossils; upon it rests the London 
clay, a fat clay, with many marly concretions and shells, as well as remains 
of turtles and crocodiles ; then follows the Bagshot sand, a sandy marl, with 
numerous marine fossils, and a non-fossiliferous sandstone. In the southern 
part of the English Bagshot sand, in the Isle of Wight, and on the coast of 
Hampshire, large beds of marine strata alternate with fresh water, consisting 
of greenish limestone, marls, and sand beds, in which are found remains of 
reptiles, Anoplotherium, and Paleotherium. 
In Provence, in the calcaire grossier, there is found a bed of coal, 
intermediate between lignite and peat; it contains remains of various 
imsects, especially of the Coleoptera. This formation is known in Germany, 
securring here and there in single patches, as in Mecklenburg, near 
Kressenberg and Sondhofen in Bavaria, and in Mark Brandenburg; also, in 
France, England, Hungary, Southern Russia, Upper Italy, in North 
America, and the East Indies. 
Molasse, or Upper Tertiary. Quite loose sandy, marly, or argillaceous 
masses have the preponderance. There are numerous mammalia in great 
variety, and of known forms. The principal rock species are : 
Nagel-fluh, which passes into sandstone and marl. 
Sand and sandstones, especially marly, argillaceous, calcareous, and 
lerruginous, frequently colored by chlorite and mixed with mica. They 
often contain concretions of lime and hydrated oxyde of iron, and pass into 
quartz-sandstone and quartz-grit. . 
Loess and loam. Leess is only a very fine well-washed loam, occurring 
over considerable tracts. 
Clay, in the different varieties, as porcelain, potter’s, pipe-, marl-clay, &e. 
Not seldom it is bituminous and aluminous, and contains, as foreign admix- 
tures, iron and arsenical pyrites, sulphur, gypsum, spherosiderite, celestine, 
and a granular clay iron-stone. 
Marl, as calcareous and argillaceous marl, which are often mixed with 
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