Page:A Treatise on Geology, volume 1.djvu/274

in a series of three terms, the upper one of which does not exist at all in the basin of Paris; while, on the other hand, the lower one, well developed near Paris, is only locally seen in the south.

Upper term	$\left\{{\begin{matrix}\ \\\\\\\ \end{matrix}}\right.$	Composed principally of beds of pebbles, sands, and coarse sandy clays, which appear all to be eminently detrital formations, so that Elie de Beaumont formerly called them 'Terrain de transport ancien.' Perpignan L offers the best type of these beds.
Middle term	$\left\{{\begin{matrix}\ \\\\\\\\\\\\\ \end{matrix}}\right.$	Comprising a great variety of deposits, partly freshwater and partly marine; freshwater deposits of limestone on hills (Agenois, Provence); sands and pebbles (faluns) on the plains (Landes); sands and marls (molasse) in low hills in Languedoc; conglomerates at Pau; gypsum and lignites at Aix, and in Provence; concretionary limestones (calcaire moellon) at Montpellier. It contains locally sulphur, and generally iron ore. These variations are the result of local circumstances influencing the borders of an oceanic basin.
Lower term	$\left\{{\begin{matrix}\ \\\\\ \end{matrix}}\right.$	Chiefly consists of calcaire grossier, and this is almost confined to the 'Landes' between the A dour and Garonne. The beds of limestone alternate with marls and clays, and rest on the cretaceous rocks. They are full of miliolites.

The middle term of this series corresponds to the upper term of Paris: it expands greatly in Spain and Switzerland.

In Spain abundance of freshwater deposits occur; in Switzerland the sandy and conglomerate beds (molasse) expand into a vast thickness, include beds of limestone and layers of lignite yielding bones, and extend along the north front of the oolites of the Alps towards Vienna. Here in the basin of Lower Styria, Murchison and Sedgwick give us the following general section of the tertiary series.